Indicate variable equipment stats

[neoancient]

Depends on MegaMek/megamek#1715

1. Makes a distinction between equipment that has a weight/cost/BV/critical slots requirement of zero and equipment that is variable.
2. BA, ProtoMechs, and small support vehicles show equipment weight by kg for everything rather than just what is < 0.1 tons. Anything >= 5 tons is filtered out for small support vehicles.
3. Equipment shown as kg is shown as a whole number, with the exception of BA ammo, has official weights of partial kg.
4. Fixed a bug introduced in my last equipment tab fix that had ammo, weapons, and structural components showing on the BA equipment tab in the "other" category.

Fixes #487

[Windchild292]

Changes look good