Initial gemspec
Concept spikes
Turn grit diffs into code sets.
Introduce CodeSets to manage changes to a file.
rename a method.  write some pending specs.
Diff from the index instead of the last commit.
Ignore the tmp directory
Break out git-specific code.
Change diffs working.

All the pieces are present, but it is not quite useful.  The coverage
formatter will fire an exception only if the uncovered source lines
and the changed lines match exactly.  Not really useful yet.

The equality check between two CodeChange objects needs to return true
if there is a non-empty intersection between the two source listings.
Change set equality

Changes are now "eql" if they have overlapping source lines.
Update dependencies
Allow diff version to be customized
Update dependencies
Implement configuration and startup helper.
Rename
License