Cleanup build script re: submodule.
Cleanup build script re: submodule.

Trying to plan for different states. If a user removes the nta dir
submodule, this will put it back before initializing the submodule. Also
cleans up after build in a cleanup function.

scottpurdy/nupic,alfonsokim/nupic,numenta-ci/nupic,neuroidss/nupic,passiweinberger/nupic,akhilaananthram/nupic,cngo-github/nupic,ywcui1990/nupic,rhyolight/nupic,brev/nupic,ywcui1990/nupic,numenta-ci/nupic,EricSB/nupic,markneville/nupic,vamsirajendra/nupic,chanceraine/nupic,darshanthaker/nupic,SaganBolliger/nupic,BoltzmannBrain/nupic,subutai/nupic,rayNymous/nupic,EricSB/nupic,vitaly-krugl/nupic,breznak/nupic,numenta-ci/nupic,runt18/nupic,GeraldLoeffler/nupic,rhyolight/nupic,sambitgaan/nupic,marionleborgne/nupic,numenta/nupic,breznak/nupic,chen0031/nupic,mcanthony/nupic,alfonsokim/nupic,elkingtonmcb/nupic,GeraldLoeffler/nupic,mcanthony/nupic,ben-hopps/nupic,pulinagrawal/nupic,go-bears/nupic,blueburningcoder/nupic,scottpurdy/nupic,lscheinkman/nupic,rcrowder/nupic,cogmission/nupic,pap/nupic,eranchetz/nupic,arhik/nupic,fergalbyrne/nupic,chen0031/nupic,ben-hopps/nupic,cngo-github/nupic,chanceraine/nupic,lscheinkman/nupic,BeiLuoShiMen/nupic,pulinagrawal/nupic,wanghaven/nupic,arhik/nupic,virneo/nupic,rayNymous/nupic,ywcui1990/nupic,BoltzmannBrain/nupic,rcrowder/nupic,metaml/nupic,BoltzmannBrain/nupic,go-bears/nupic,GeraldLoeffler/nupic,rayNymous/nupic,eranchetz/nupic,fergalbyrne/nupic,blueburningcoder/nupic,loretoparisi/nupic,brev/nupic,numenta/nupic,wanghaven/nupic,darshanthaker/nupic,EricSB/nupic,glorizen/nupic,chanceraine/nupic,badlogicmanpreet/nupic,cogmission/nupic,cngo-github/nupic,allanino/nupic,passiweinberger/nupic,brev/nupic,SaganBolliger/nupic,loretoparisi/nupic,passiweinberger/nupic,subutai/nupic,markneville/nupic,breznak/nupic,neuroidss/nupic,badlogicmanpreet/nupic,darshanthaker/nupic,SaganBolliger/nupic,fergalbyrne/nupic,sambitgaan/nupic,rhyolight/nupic,jcasner/nupic,virneo/nupic,akhilaananthram/nupic,glorizen/nupic,glorizen/nupic,scottpurdy/nupic,ben-hopps/nupic,elkingtonmcb/nupic,allanino/nupic,cogmission/nupic,vamsirajendra/nupic,runt18/nupic,jcasner/nupic,marionleborgne/nupic,numenta/nupic,elkingtonmcb/nupic,lscheinkman/nupic,metaml/nupic,badlogicmanpreet/nupic,subutai/nupic,pap/nupic,rcrowder/nupic,virneo/nupic,eranchetz/nupic,mcanthony/nupic,go-bears/nupic,wanghaven/nupic,sambitgaan/nupic,BeiLuoShiMen/nupic,metaml/nupic,loretoparisi/nupic,vitaly-krugl/nupic,vitaly-krugl/nupic,blueburningcoder/nupic,runt18/nupic,neuroidss/nupic,markneville/nupic,BeiLuoShiMen/nupic,pap/nupic,jcasner/nupic,akhilaananthram/nupic,allanino/nupic,vamsirajendra/nupic,chen0031/nupic,marionleborgne/nupic,pulinagrawal/nupic,arhik/nupic,alfonsokim/nupic