Implement formatting coins with commas.

[stevewgr]

Description

This PR implements formatting coins with commas as per behavior in the official client.

I hope I didn't miss anything, but I believe it should cover most scenarios: Trade, Buy / Sell, Warehouse, Inventory, Item repair and vice versa.

Note for the reviewer: This PR is on top of another branch that hasn't been merged yet. Please review the following two commits:

• https://github.com/ko4life-net/ko/commit/097634f7e766aa857ed86b2e74352cbed7052bd4
• https://github.com/ko4life-net/ko/commit/66d9c845964ee2d2acc0dd8f1e72d17288e38353