Add testing helpers for mocking and encoding tests.
Add testing helpers for mocking and encoding tests.

pandas.util.testing now has a SimpleMock class for mocking objects which
have read-only attributes.
Ths mocking support is used by the *stdin_encoding* context manager to
make it easy to test code with an arbitrary value for sys.stdin.encoding.

cython-testbed/pandas,pandas-dev/pandas,zfrenchee/pandas,amolkahat/pandas,louispotok/pandas,toobaz/pandas,dsm054/pandas,zfrenchee/pandas,harisbal/pandas,winklerand/pandas,rs2/pandas,Winand/pandas,louispotok/pandas,GuessWhoSamFoo/pandas,jorisvandenbossche/pandas,winklerand/pandas,louispotok/pandas,jorisvandenbossche/pandas,TomAugspurger/pandas,zfrenchee/pandas,linebp/pandas,jorisvandenbossche/pandas,nmartensen/pandas,jmmease/pandas,TomAugspurger/pandas,gfyoung/pandas,pandas-dev/pandas,gfyoung/pandas,louispotok/pandas,kdebrab/pandas,zfrenchee/pandas,amolkahat/pandas,DGrady/pandas,Winand/pandas,DGrady/pandas,harisbal/pandas,jmmease/pandas,cbertinato/pandas,dsm054/pandas,datapythonista/pandas,kdebrab/pandas,MJuddBooth/pandas,rs2/pandas,jreback/pandas,nmartensen/pandas,dsm054/pandas,harisbal/pandas,pratapvardhan/pandas,toobaz/pandas,winklerand/pandas,DGrady/pandas,MJuddBooth/pandas,harisbal/pandas,datapythonista/pandas,jmmease/pandas,TomAugspurger/pandas,nmartensen/pandas,linebp/pandas,linebp/pandas,toobaz/pandas,zfrenchee/pandas,pandas-dev/pandas,kdebrab/pandas,Winand/pandas,cython-testbed/pandas,GuessWhoSamFoo/pandas,louispotok/pandas,pratapvardhan/pandas,GuessWhoSamFoo/pandas,jmmease/pandas,rs2/pandas,winklerand/pandas,gfyoung/pandas,harisbal/pandas,winklerand/pandas,jorisvandenbossche/pandas,TomAugspurger/pandas,jreback/pandas,nmartensen/pandas,toobaz/pandas,Winand/pandas,kdebrab/pandas,Winand/pandas,MJuddBooth/pandas,cbertinato/pandas,rs2/pandas,pandas-dev/pandas,MJuddBooth/pandas,jreback/pandas,cython-testbed/pandas,MJuddBooth/pandas,cython-testbed/pandas,gfyoung/pandas,nmartensen/pandas,pratapvardhan/pandas,datapythonista/pandas,kdebrab/pandas,linebp/pandas,nmartensen/pandas,dsm054/pandas,dsm054/pandas,linebp/pandas,cbertinato/pandas,jmmease/pandas,pratapvardhan/pandas,jreback/pandas,linebp/pandas,winklerand/pandas,amolkahat/pandas,cbertinato/pandas,cbertinato/pandas,GuessWhoSamFoo/pandas,Winand/pandas,toobaz/pandas,amolkahat/pandas,cython-testbed/pandas,jmmease/pandas,jreback/pandas,gfyoung/pandas,DGrady/pandas,amolkahat/pandas,GuessWhoSamFoo/pandas,DGrady/pandas,DGrady/pandas,datapythonista/pandas,pratapvardhan/pandas