Fixing badly indendted end
Pinata::SCM::Git tests to be in a sandbox repo
Added SCM abstractiob/loookup via Pinata::SCM.

* Code from lib/pinata/scm.rb was moved into lib/pinata/scm/git.rb
* lib/pinata/scm.rb had scm operation added to return the scm to
  work with.  Its current impl is just to return Pinata::SCM::Git.
Added Pinata::SCM::Git.local_modifications; Proper sandboxing
Added Pinata::SCM::Git#modified_files
Reorganizing contents of Pinata::SCM::Git
Pinata::SCM::Git public API docs
Failing test for Pinata::SCM::Git#local_contents_of
Implemented Pinata::SCM::Git@local_content_of
Added Pinata::SCM::Git#remote_contents_of method.
Rearranged git sandbox to better support sandboxes for other scms