Using Coveralls helps us fix #13

This should get you started using the free (open source)
tier of Coveralls. It adds a nice badge to your project
page (see README.md) with the coverage percentage on it,
and you can get a log of percentage per Travis CI build.

Having never used Coveralls before, I hope this'll work.
Move trait_exists(), interface_exists(), class_exists() to Util::classIsDefined(), except for a few performance-critical places.
Ignore the MapLeak stuff in code coverage for now. It is to be considered 'under construction'.
Get the interface right for NamespaceInspector_Pluggable.
Introduce Adapter_* as a replacement for RegistrationHub.
Merge branch 'feature/coveralls' of git://github.com/paul-vg/krautoload into paul-vg-feature/coveralls