Make large tables sortable

[laomaiweng]

Hi, and first of all thank you for this awesome tool! I switched over from CFF Explorer with the release of PE-bear 0.5.0 and I'm not looking back. :)

I'd just like to suggest a minor GUI enhancement: make some tables sortable, particularly the GuardCFFunctionTable and Exported Functions tables. These tables may contain upwards of 2k entries for e.g. ntdll.dll, and are presented in Offset order.
It would make looking things up inside those tables that much easier if they could be sorted by any of their other columns.

[hasherezade]

Thank you, that's a good suggestion! I will try to make it ready for the next release.