Added installation instructions to README
Added additional information on requirements / extensibility to the
overview.
Added instructions for running the tool using nosetests and coverage.py
Merge pull request #17 from edx/will/readme-revision

README revisions
Merge pull request #18 from edx/cale/violation-reporter

Generalize BaseCoverageReporter to BaseViolationsReporter
Merge branch 'master' into will/jinja2-templates