Added support for cache dictionary for select method. This allows finer-grained cache invalidation.
Added support for cache dictionary for select method. This allows finer-grained cache invalidation.

kmcheung12/pydal,michele-comitini/pydal,web2py/pydal,willimoa/pydal,niphlod/pydal,stephenrauch/pydal,manuelep/pydal