TST: Catch possible warnings
TST: Catch possible warnings

Previously the test sometimes fails with the following error:

======================================================================
ERROR: Test a special case for var
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Traceback (most recent call last):
  File "/home/travis/virtualenv/python3.2/lib/python3.2/site-packages/numpy/ma/tests/test_core.py", line 2731, in test_varstd_specialcases
    _ = method(out=mout)
  File "/home/travis/virtualenv/python3.2/lib/python3.2/site-packages/numpy/ma/core.py", line 4778, in std
    np.power(out, 0.5, out=out, casting='unsafe')
RuntimeWarning: invalid value encountered in power

----------------------------------------------------------------------

Now we catch it, as recommended by the thread:

http://old.nabble.com/Should-abs(-nan-)-be-supported--td34389839.html

ewmoore/numpy,pyparallel/numpy,leifdenby/numpy,mhvk/numpy,endolith/numpy,joferkington/numpy,ViralLeadership/numpy,GrimDerp/numpy,rudimeier/numpy,leifdenby/numpy,simongibbons/numpy,githubmlai/numpy,madphysicist/numpy,nguyentu1602/numpy,jankoslavic/numpy,dch312/numpy,tdsmith/numpy,trankmichael/numpy,ahaldane/numpy,GrimDerp/numpy,njase/numpy,KaelChen/numpy,Eric89GXL/numpy,githubmlai/numpy,madphysicist/numpy,musically-ut/numpy,grlee77/numpy,gmcastil/numpy,tdsmith/numpy,mingwpy/numpy,naritta/numpy,SiccarPoint/numpy,felipebetancur/numpy,immerrr/numpy,pizzathief/numpy,tynn/numpy,jschueller/numpy,hainm/numpy,GaZ3ll3/numpy,SiccarPoint/numpy,jorisvandenbossche/numpy,dato-code/numpy,dwillmer/numpy,GrimDerp/numpy,bmorris3/numpy,SunghanKim/numpy,abalkin/numpy,Linkid/numpy,rhythmsosad/numpy,dimasad/numpy,anntzer/numpy,WarrenWeckesser/numpy,githubmlai/numpy,yiakwy/numpy,naritta/numpy,MSeifert04/numpy,dwf/numpy,seberg/numpy,MSeifert04/numpy,ContinuumIO/numpy,maniteja123/numpy,NextThought/pypy-numpy,mattip/numpy,brandon-rhodes/numpy,sonnyhu/numpy,behzadnouri/numpy,chiffa/numpy,pdebuyl/numpy,rgommers/numpy,jorisvandenbossche/numpy,empeeu/numpy,WillieMaddox/numpy,ddasilva/numpy,BMJHayward/numpy,kiwifb/numpy,dwf/numpy,hainm/numpy,numpy/numpy,Yusa95/numpy,andsor/numpy,tynn/numpy,mathdd/numpy,joferkington/numpy,MichaelAquilina/numpy,empeeu/numpy,drasmuss/numpy,b-carter/numpy,SunghanKim/numpy,MaPePeR/numpy,tdsmith/numpy,BMJHayward/numpy,yiakwy/numpy,jakirkham/numpy,jonathanunderwood/numpy,nguyentu1602/numpy,embray/numpy,pizzathief/numpy,BMJHayward/numpy,shoyer/numpy,cjermain/numpy,ESSS/numpy,KaelChen/numpy,skymanaditya1/numpy,stuarteberg/numpy,madphysicist/numpy,sigma-random/numpy,behzadnouri/numpy,dimasad/numpy,dwillmer/numpy,ContinuumIO/numpy,kiwifb/numpy,chatcannon/numpy,kirillzhuravlev/numpy,jakirkham/numpy,ContinuumIO/numpy,felipebetancur/numpy,larsmans/numpy,stuarteberg/numpy,rhythmsosad/numpy,bmorris3/numpy,ewmoore/numpy,skymanaditya1/numpy,KaelChen/numpy,chiffa/numpy,mathdd/numpy,jorisvandenbossche/numpy,naritta/numpy,kirillzhuravlev/numpy,MSeifert04/numpy,gmcastil/numpy,dimasad/numpy,simongibbons/numpy,utke1/numpy,mortada/numpy,groutr/numpy,shoyer/numpy,kiwifb/numpy,WarrenWeckesser/numpy,dimasad/numpy,bringingheavendown/numpy,GrimDerp/numpy,rudimeier/numpy,SunghanKim/numpy,mhvk/numpy,rajathkumarmp/numpy,dch312/numpy,BabeNovelty/numpy,immerrr/numpy,Yusa95/numpy,ajdawson/numpy,groutr/numpy,mwiebe/numpy,rmcgibbo/numpy,rhythmsosad/numpy,stuarteberg/numpy,njase/numpy,dato-code/numpy,moreati/numpy,rgommers/numpy,njase/numpy,ahaldane/numpy,dwillmer/numpy,MSeifert04/numpy,bringingheavendown/numpy,kirillzhuravlev/numpy,mathdd/numpy,shoyer/numpy,simongibbons/numpy,trankmichael/numpy,jakirkham/numpy,grlee77/numpy,jakirkham/numpy,AustereCuriosity/numpy,jonathanunderwood/numpy,sinhrks/numpy,cowlicks/numpy,moreati/numpy,argriffing/numpy,embray/numpy,pdebuyl/numpy,Yusa95/numpy,mingwpy/numpy,embray/numpy,ChristopherHogan/numpy,SiccarPoint/numpy,mattip/numpy,pbrod/numpy,bertrand-l/numpy,behzadnouri/numpy,hainm/numpy,skwbc/numpy,moreati/numpy,sinhrks/numpy,sinhrks/numpy,mingwpy/numpy,charris/numpy,bertrand-l/numpy,BabeNovelty/numpy,skymanaditya1/numpy,WillieMaddox/numpy,Eric89GXL/numpy,joferkington/numpy,mingwpy/numpy,pizzathief/numpy,pyparallel/numpy,brandon-rhodes/numpy,ahaldane/numpy,yiakwy/numpy,ewmoore/numpy,pizzathief/numpy,utke1/numpy,Eric89GXL/numpy,CMartelLML/numpy,simongibbons/numpy,tacaswell/numpy,endolith/numpy,Linkid/numpy,ewmoore/numpy,ESSS/numpy,ddasilva/numpy,rmcgibbo/numpy,ChanderG/numpy,numpy/numpy,sonnyhu/numpy,ekalosak/numpy,cjermain/numpy,jankoslavic/numpy,numpy/numpy,hainm/numpy,Anwesh43/numpy,GaZ3ll3/numpy,drasmuss/numpy,rajathkumarmp/numpy,leifdenby/numpy,sonnyhu/numpy,b-carter/numpy,Linkid/numpy,b-carter/numpy,rgommers/numpy,ajdawson/numpy,ChristopherHogan/numpy,anntzer/numpy,jschueller/numpy,empeeu/numpy,argriffing/numpy,madphysicist/numpy,bmorris3/numpy,githubmlai/numpy,abalkin/numpy,rudimeier/numpy,endolith/numpy,brandon-rhodes/numpy,Srisai85/numpy,seberg/numpy,pbrod/numpy,SunghanKim/numpy,musically-ut/numpy,ahaldane/numpy,MichaelAquilina/numpy,ekalosak/numpy,rmcgibbo/numpy,WarrenWeckesser/numpy,ddasilva/numpy,cowlicks/numpy,rgommers/numpy,drasmuss/numpy,ChanderG/numpy,bmorris3/numpy,madphysicist/numpy,dwf/numpy,mathdd/numpy,pbrod/numpy,skwbc/numpy,AustereCuriosity/numpy,ViralLeadership/numpy,jorisvandenbossche/numpy,charris/numpy,BabeNovelty/numpy,ESSS/numpy,argriffing/numpy,felipebetancur/numpy,cjermain/numpy,immerrr/numpy,CMartelLML/numpy,musically-ut/numpy,dch312/numpy,stuarteberg/numpy,nguyentu1602/numpy,NextThought/pypy-numpy,mindw/numpy,rajathkumarmp/numpy,ChristopherHogan/numpy,NextThought/pypy-numpy,sinhrks/numpy,rhythmsosad/numpy,ssanderson/numpy,empeeu/numpy,MaPePeR/numpy,ahaldane/numpy,gfyoung/numpy,larsmans/numpy,Dapid/numpy,mortada/numpy,trankmichael/numpy,chatcannon/numpy,rudimeier/numpy,WillieMaddox/numpy,dwf/numpy,jankoslavic/numpy,numpy/numpy,mattip/numpy,gfyoung/numpy,MSeifert04/numpy,WarrenWeckesser/numpy,Anwesh43/numpy,Anwesh43/numpy,seberg/numpy,pdebuyl/numpy,NextThought/pypy-numpy,pyparallel/numpy,solarjoe/numpy,AustereCuriosity/numpy,dwillmer/numpy,has2k1/numpy,sigma-random/numpy,rherault-insa/numpy,maniteja123/numpy,anntzer/numpy,ChanderG/numpy,grlee77/numpy,sonnyhu/numpy,jakirkham/numpy,shoyer/numpy,joferkington/numpy,grlee77/numpy,Dapid/numpy,pizzathief/numpy,cowlicks/numpy,andsor/numpy,ajdawson/numpy,ogrisel/numpy,abalkin/numpy,nbeaver/numpy,jschueller/numpy,ogrisel/numpy,solarjoe/numpy,anntzer/numpy,ChristopherHogan/numpy,naritta/numpy,jonathanunderwood/numpy,dch312/numpy,mwiebe/numpy,Srisai85/numpy,mhvk/numpy,brandon-rhodes/numpy,CMartelLML/numpy,nbeaver/numpy,Srisai85/numpy,pbrod/numpy,simongibbons/numpy,felipebetancur/numpy,yiakwy/numpy,ogrisel/numpy,solarjoe/numpy,jankoslavic/numpy,sigma-random/numpy,Yusa95/numpy,embray/numpy,mattip/numpy,pdebuyl/numpy,shoyer/numpy,ewmoore/numpy,cjermain/numpy,rmcgibbo/numpy,tacaswell/numpy,jorisvandenbossche/numpy,ogrisel/numpy,ajdawson/numpy,dato-code/numpy,andsor/numpy,mortada/numpy,mindw/numpy,bertrand-l/numpy,ssanderson/numpy,gfyoung/numpy,SiccarPoint/numpy,pbrod/numpy,ogrisel/numpy,ekalosak/numpy,chiffa/numpy,gmcastil/numpy,bringingheavendown/numpy,ViralLeadership/numpy,MaPePeR/numpy,Eric89GXL/numpy,embray/numpy,KaelChen/numpy,cowlicks/numpy,trankmichael/numpy,jschueller/numpy,has2k1/numpy,andsor/numpy,musically-ut/numpy,mortada/numpy,MichaelAquilina/numpy,CMartelLML/numpy,rajathkumarmp/numpy,seberg/numpy,WarrenWeckesser/numpy,ssanderson/numpy,maniteja123/numpy,grlee77/numpy,groutr/numpy,BabeNovelty/numpy,tacaswell/numpy,chatcannon/numpy,has2k1/numpy,rherault-insa/numpy,GaZ3ll3/numpy,Dapid/numpy,ekalosak/numpy,utke1/numpy,MichaelAquilina/numpy,dato-code/numpy,mindw/numpy,larsmans/numpy,mhvk/numpy,Linkid/numpy,MaPePeR/numpy,dwf/numpy,GaZ3ll3/numpy,charris/numpy,skwbc/numpy,mwiebe/numpy,mhvk/numpy,rherault-insa/numpy,larsmans/numpy,tynn/numpy,Anwesh43/numpy,nbeaver/numpy,immerrr/numpy,skymanaditya1/numpy,kirillzhuravlev/numpy,sigma-random/numpy,nguyentu1602/numpy,Srisai85/numpy,BMJHayward/numpy,has2k1/numpy,ChanderG/numpy,endolith/numpy,charris/numpy,mindw/numpy,tdsmith/numpy