additional common.is_*_dtype tests in core.common
make better use of dtype tests in nanops
TST: Remove else after except in tests for io.data.Options.

Made the old tests consistent with the new tests, also passed the RemoteDataError on skip.

CLN:  Moved test for no tables to the get_option_tables method.
Merge pull request #7564 from dstephens99/master

TST: Remove else after except in tests for io.data.Options.
Merge pull request #7547 from toddrjen/nanopsclean

Minor cleanups for nanops
WIP: select_dtypes impl