Block Stats: Add output filtering.

Valid formats for block names/filters are:
- 'stone' (only for vanilla blocks, the prefix 'minecraft:' will be added
  automatically if no ':' character is found.
- 'ThermalFoundation:Ore' (modid:blockname format. Will match all blocks
  of that type regardless of metadata.)
- 'ThermalFoundation:Ore:1' (Will match the modid:blockname AND meta.)

Note: To filter by metadata, the modid part is required!
So 'obsidian:0' will not work, but 'minecraft:obsidian:0' will work.

Example:
/tellme blockstats count masa_ 16 16 16
/tellme blockstats query ThermalFoundation:Ore:0 ThermalFoundation:Ore:1
enderutilities:enderfurnace

Also note, that only the count subcommand will actually count the blocks
from the world. The query and dump commands will just output the data from
the previous count command. So if you want to re-count, just run the count
command again.