1.6 Update

[simplyWiri]

This has turned into a patch to fix an annoying bug.

• Bill polish: When a tag is not selected the bill will appear suspended
• Show basic stat offsets in loadout editor panel
• Enable sorting by items by their stat offsets, enable filtering by whether or not they have been researched or not
• Add ability to press enter to select in the tag selector UI
• Fix errors which occur when removing mods which add stuffs, and having items/apparel around without a non-null stuff

[simplyWiri]

Closes #64