Merge the GO changes dfighter2->Master part 29

ADDED: GO_Destructible class. Implements type 33 ( DESTRUCTIBLE ) GameObjects!

ADDED: .go damage < damage > < spellid >  -  damages the destructible GO for < damage > with spell < spellid >
       .go rebuild - rebuilds the destructible GameObject, restores it to defaults.

Thanks a bunch to Trinitycore and Silinoron for the research done regarding flags, packets, structures, etc :)

MERGE: Finished -> related to issue #150