v1.6.0 - Integrate unit conversion for kg

International tabletop fans rejoice, for encumbrance figures can now be shown in kg!
In options, you'll find a toggle between pounds, kilograms-lazy, and kilograms.

• Pounds is the usual behavior from versions before this one. All weights will be displayed (unlabeled) as pounds.
• Kilograms-lazy uses kg for values on the sheet other than per-item weights and equipment total weight. This allows off-the-shelf modules to be used with minimal exposure to these foreign standards.
• Kilograms uses kg values everywhere, but requires that you change all the items in your game database accordingly, which is time consuming.

As usual, this release also includes restructuring and a variety of miscellaneous (hopefully beneficial) changes.