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/route_16_gate.asm

@@ -1,22 +1,22 @@
-_UnnamedText_49777: ; 8cca0 (23:4ca0)
+_UnnamedText_49777:: ; 8cca0 (23:4ca0)
 	text "No pedestrians"
 	line "are allowed on"
 	cont "CYCLING ROAD!"
 	done
 
-_UnnamedText_4977c: ; 8cccd (23:4ccd)
+_UnnamedText_4977c:: ; 8cccd (23:4ccd)
 	text "CYCLING ROAD is a"
 	line "downhill course"
 	cont "by the sea. It's"
 	cont "a great ride."
 	done
 
-_UnnamedText_49781: ; 8cd0e (23:4d0e)
+_UnnamedText_49781:: ; 8cd0e (23:4d0e)
 	text "Excuse me! Wait"
 	line "up please!"
 	done
 
-_Route16GateMapText2: ; 8cd2a (23:4d2a)
+_Route16GateMapText2:: ; 8cd2a (23:4d2a)
 	text "How'd you get in?"
 	line "Good effort!"
 	done