Get rid of globals.asm. Use ::s to export labels between objects.

globals.asm was a hack that:
- gave rgbasm an extra 100k lines to read
- increased reliance on the python preprocessor
- made the makefile a mess
- gave object creation an extra step
- wasn't even necessary

This speeds up build time by at least a third.

text/maps/vermilion_pokecenter.asm

@@ -1,5 +1,5 @@
-_VermilionPokecenterText2: ; 9a4b2 (26:64b2)
-_VermilionPokecenterText1: ; 9a4b2 (26:64b2)
+_VermilionPokecenterText2:: ; 9a4b2 (26:64b2)
+_VermilionPokecenterText1:: ; 9a4b2 (26:64b2)
 	text "Even if they are"
 	line "the same level,"
 	cont "#MON can have"
@@ -12,7 +12,7 @@ _VermilionPokecenterText1: ; 9a4b2 (26:64b2)
 	cont "in the wild."
 	done
 
-_VermilionPokecenterText3: ; 9a539 (26:6539)
+_VermilionPokecenterText3:: ; 9a539 (26:6539)
 	text "My #MON was"
 	line "poisoned! It"
 	cont "fainted while we"