Added support for copy-command. closes #4
Added octopress to dev dependencies
Updated file asset type

No longer is there a Root File asset. Now File assets will copy to a
site much like page assets. The path will match the location in the
files directory. so plugin_assets/files/robots.txt will end up in
_site/robots.txt.

Much like page assets, files will match their plugin path and can be
installed anywhere unless there is a file in that location. Also files
in _plugins/files/whatever will overwrite the plugin path.
Fixed tests
Perhaps this will appease Travis
Oh Travis... please.
Refactoring assets pipeline

- Added new local asset type for clearer separation of roles.
- Now reading sass configuration in a manner compatible with Sass 2.0
- Now all assets except for CSS and Sass are automatically added to plugins.
- Now requiring the Octopress gem as a runtime dependency
Comment out local test stuff in test Gemfile
sanity refactor responding to PR comments
removed duplication when adding plugin assets
attr_reader all the things
Merge pull request #8 from octopress/copy-command

Copy command