swars: Separate module for drawins special in-game text

The game contains two custom text drawing functions: wave
coloured text (for mission complete message) and bordered
text (for MP chat messages).

This change separates those special drawing methods, while
also making a copy of bflibrarys text draw functions in
order to use universal template for the altered drawing.

Author: mefistotelis

src/Makefile.am

@@ -10,6 +10,8 @@ swars_SOURCES = \
 	ap_gspr_map.c \
 	ap_spr_smap.c \
 	app_sprite.h \
+	app_text.c \
+	app_text.h \
 	bflib_joyst.c \
 	bflib_joyst.h \
 	bflib_joyst_s.sx \