layouts: add support for configuring branches directory This should work for both alternately named directories (e.g. releases instead of branches), as well as subdirs (branches/releases), and combinations thereof (releases/public).

syntax:glob
build
*.pyc
*.pyo
.DS_Store
*.swp
*~
.coverage
cover
*.py,cover
MANIFEST
dist
*.egg-info
hgsubversion/__version__.py
nbproject
.project
.pydevproject
.settings
*.orig
.noseids
tests/fixtures/temp