This is source code of BOBJ exporter add-on for Blender 2.7.*. BOBJ is an extension of OBJ format that provides also vertex weights, armature information and bone animations (in form of keyframes). It's used by S&B Minecraft mod.
This add-on is based (i.e. modified to suit my format needs) on the bundled io_scene_obj Blender add-on (written by Campbell Barton and Bastien Montagne) which is under GPL license (see Python source code for license header). To comply with GPL license, the list of changes from the original source code is available in CHANGES.md.
To install this add-on, download this file, open Blender 2.7.*, File > User Preferences > Add-ons > Install Add-on From File... and pick the ZIP you downloaded in Blender's file browser.
After that, the exporter menu item should be available under File > Export. If it's not, make sure that the add-on is enabled in Add-ons tab of User Preferences!
To install this add-on, download this file, open Blender 2.8+, Edit > Preferences > Add-ons > Install... and pick the ZIP you downloaded in Blender's file browser. Once the add-on will appear in the list, enable it.
After that, the exporter menu item should be available under File > Export. If it's not, make sure that the add-on is enabled in Add-ons tab of User Preferences!