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/saffron_mart.asm

@@ -1,4 +1,4 @@
-_SaffronMartText2: ; a23e3 (28:63e3)
+_SaffronMartText2:: ; a23e3 (28:63e3)
 	text "MAX REPEL lasts"
 	line "longer than SUPER"
 	cont "REPEL for keeping"
@@ -6,7 +6,7 @@ _SaffronMartText2: ; a23e3 (28:63e3)
 	cont "away!"
 	done
 
-_SaffronMartText3: ; a242a (28:642a)
+_SaffronMartText3:: ; a242a (28:642a)
 	text "REVIVE is costly,"
 	line "but it revives"
 	cont "fainted #MON!"