Compatibility patches for Minecraft 1.7.10

Organize repo to use ForgeGradle.
Fix Minecraft mappings.
Update to the sound system.
Update to the localization system.
Merge the "achievement icon" item into an unobtainable ammo.
Aether "main menu" support dropped, since this mod isn't up to 1.7.

--Untested--
Probably not compatible with old saves, due to a vanilla change in living (ie turrets) health data.
Should be multiplayer compatible.