Converted build_src to using json format.
Converted build_src to using json format.

* Final overhaul to move to json format.
* Use dict.get so that empty cmds/globs not needed.

starcraftman/.my_scripts,starcraftman/.my_scripts,starcraftman/.my_scripts,starcraftman/.my_scripts,starcraftman/.my_scripts,starcraftman/.my_scripts,starcraftman/.my_scripts