Add metrics, as suggested by @Burckhart

@Wickth, if you don't like it, just revert this commit.

http://mcstats.org/plugin/TerrainControl (currently empty, but that will
soon change)

The following data will be tracked:
- Number of players/servers using the plugin
- Java version
- Operating system + version
- Authentication mode (online/offline mode)
- MCStats version
- System architecture (32/64 bits)
- Number of system cores
- Game version (1.5.2/1.6.1/etc.)
- Server software (CraftBukkit/Forge/Spigot/etc.)
- TerrainControl version
- Server location (Germany/Russia/Netherlands/United States/etc.)
- Biome mode (Normal/FromImage/etc.)

The metrics are optional, you can switch them off in
plugins/Metrics/config.yml (Bukkit-based servers) or
config/PluginMetrics.cfg (Forge-based servers)

Also fixed the id:data syntax in BO3's BlockChecks.