Fix the column selection mechanism of the TransposeTable filter.

As ParaView (and pqTreeView) sort table columns in alphabetical
order, it is important that selected columns are added in the
sub table used for transposition with their original order in
the input table and not according the alphabetical order.

Change-Id: I714657d255340ce0d4c0bd6dc7520fec3e4e9dfa
BUG: 14824. Fix GetReaders().

Fixed logic in GetReaders when the filename is empty. The method is
supposed to return all possible readers, but due to a copy-paste error
it just returned an empty list.

Change-Id: Ida60f513ed152c8b6e9d1e3544d2503c60ec8b1f
Merge topic '14824_fix_reader_factory' into next

a10e3081 BUG: 14824. Fix GetReaders().
Getting rid of a compiler warning.

Change-Id: I10432119232f3e8a4671899e79d2fbd988201194
Merge topic '14784_PythonCatalyst_better_IO_2' into next

1d79ffdd Getting rid of a compiler warning.
Merge topic 'fix-pv-transposetable-filter' into next

59929d1a Fix the column selection mechanism of the TransposeTable filter.