A simple 4Cs (Carat, Color, Clarity, Cut) gemstone model implementation.
Implementation of getgems RPC method, for translating user BTGs into gemstones.
Include gem files into bitgem-qt.pro.
Add gem sources.
Sapphire icon.
Fix 4Cs weights, add some aux methods, and some fixes.
Fix rounded stake reward and stake reward for <1 tx.
Merge branch 'sapphire'
Add checkpoints.