call it button_new instead of new

"new" is sometimes a reserved keyword and it would be nice to not use
that name.
remove two unused methods from map_editor.py
return constants after parsing
Merge branch 'master' into map-editor-stuff
Merge pull request #58 from kanzure/map-editor-stuff

Minor map editor changes
wram: try to determine addresses for section defs without any
use file includes in rgbasm objects to generate dependencies
sym: rgbds does ram banks now
wram: cleaner line parsing

fixes 0fd121a8
labels: grab labels from a mapfile instead of an old json dump

labels.json had to be deleted manually to be updated, and rgbasm is better at scanning labels anyway
preprocessor: dont write to globals.asm for each process
scan_includes: join names properly and actually use conf.path
Merge pull request #59 from yenatch/dependencies

Use a mapfile instead of labels.json; object dependency handling