Added directory specification to the README

Includes update to 0.1.0, and the inclusion of attribute descriptions
for all supported attributes. The example manifest is now also somewhat
more believable.
Merge branch 'documentation/readme-0.1.0' into dev
Merge branch 'dev' into stable
Merge branch 'stable' of github.com:sirosen/SALVE into config
Added a git function and cleaned up attrs.

There were several mode and action specifications that are redundant
with the defaults. Also adds "gco" as an alias for git-checkout.