Adding configuration files for breaking the build

These thresholds will be used to break the build, if set.
Adding istanbul check-coverage support

This implements the check-coverage report, but does not call the code
yet.
Wire up check-coverage to run after reports

If coverage thresholds are set, they will now be run after reports.
Version Bump
Adding coverage threshold command line options
Adding coverage threshold command line options
Merge branch 'check_coverage' of github.com:trevmex/teaspoon into check_coverage

Conflicts:
	lib/teaspoon/command_line.rb
Add coverage threshold command line to README
Merge pull request #149 from trevmex/check_coverage

Istanbul 'check-coverage' support in Teaspoon (Issue #147)