MONDRIAN-1771 - Introducing the DataServicesProvider.  Creating an extension point for plugging in a MemberReader.  More extension points to come.
MONDRIAN-1771 - creating an extension point for SegmentLoader
MONDRIAN-1771 - creating an extension point for DataSource.  Moved several static methods and inner classes from RolapConnection to DefaultDataServicesProvider
MONDRIAN-1771 - creating an extension point for TupleReader.  Only extending usage in RolapNativeSet.  Mondrian also creates a new SqlTupleReader inside of SqlMemberSource.  SqlMemberSource is already one of the DataServiceProvider extension points, so we don't need to extend this usage.
MONDRIAN-1771 - applying few small changes from code review
Merge pull request #176 from kurtwalker/MONDRIAN-1771

MONDRIAN-1771