Improvements to commands, added commands, added config option, fixed 2 issues

1) Added server output for /pokespawn and /freeze, for server admin visibility
--- Addresses Issue #1054 for all commands (including /pokebattle /pokeheal)

2) Fixed selection of pixelmon tile entities in creative with middle mouse button
--- Now correctly selects PC, Anvil, EvolutionRock, Fossil Cleaner, Fossil Machine, Healer, TradeMachine, instead of defaulting to icyrock
--- Creative item icons for EvolutionRocks still need to be made, added a //TODO reminder
--- Solves Issue #1048 

3) Added functioning /pokebattle <player1> <player2> command (tested and works!)
--- Allows initiation of battle between two VALID players in the same dimension

4) Added functioning /pokeheal <player> command (works with @p @a and lists)
--- command doesn't allow healing while player is in battle to avoid exploits
--- able to iterate through a list of players, healing all valid targets

5) Added config setting to adjust entity nameplate render distance …
--- applies to trainers, doctors, pixelmon entities
--- default value is 1 (16 blocks boss, 8 blocks normal) = current behavior
--- value 2 = (24 boss, 16 normal) and value 3 = (32 boss, 24 normal)
--- coded with min() max() check to prevent values outside range [1, 3]