Refactored table folder and modules

I got annoyed at the folder structure and all the extra modules/classes in the table folder (left over from the previous refactor) and refactored again.

* Moved formotion_screen into thirdparty
* Simplified GroupedTable
* Removed PM::PlainTable
* Moved RefreshableTable and SearchableTable into
PM::Table::<modulename>
* Combined table.rb and table_screen_module.rb which were similarily
focused
* Removed extraneous/redundant module SectionedTableScreen (it's just a
TableScreen)
* Moved searchable/refreshable into /extensions folder

All tests passing: 197 specifications (334 requirements), 0 failures, 0
errors