Add basic support for Coveralls reports

  - Requires the 'coveralls' gem
  - Reports lines that have created a resource that has been asserted
BUGFIX : keep module name to avoid file overwrite

Keep the module name and filter out the manifest path portion.
This allows for package alike classification, and avoids that
files in the report get overwritten, leading for a single entry
for 'manifest/init.pp' despite the number of modules covered.
Create separate function to create the coverage summary
Create a submodule for coverage reports
Add skeleton for cobertura reporter
Add global coverage rate
Include package entries on output
Add details about classes
Finish cobertura report with details about lines
Change link to TavisCI builds
* Pin rspec dependency to < 3.0.0 Fixes #200
* Fix deprecation warnings related to 'display_name', fixes #198
Merge branch 'cobertura_ready'