LazyPigMultibox.xml removal and minor changes to "CHAT_FRAME" functions.

LazyPigMultibox.xml has beed removed and the code moved to LazyPigMultibox.lua.
This change removed LazyPigMultibox_OnLoad function, as it's not used for pure-lua addons.

Variable "debug_on" is changed to "lpm_debug". Using "generic" names usually leads to errors.