Build system: fix SmartFileTask group task generation

Also ensure base is always an array.
Build system: clarify MustacheTask rationale
Build system: fix MustacheTask template requirement

Make sure we keep template in the requirements without clobbering them.
Build system: group verbosity setting for builds
Build system: changelog management

Create a canonical changelog data file (YAML format, body text GitHub
flavored Markdown) and generate all user facing changelog data via
MustacheTasks.
Changelog
Release RSS feed
Build system: fix typos
Do not add app bundles to version control