TEST io.sql: sqlite tests to seperate class
TEST io.sql: sqlite tests to seperate class

One base class for tests with sqlalchemy backend. So test classes
for mysql and postgresql don't have to overwrite tests that are
different for sqlite.

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