Update the travis.cmake to work with PR and remote branch testing.
turn down the verbosity of travis builds to make it easier to find errors.
enable full paths in gcov since we have multiples files with the same name.
Only able coverage for debug builds.

gcov is having real issues with release builds, so only use debug builds for coverage.
Merge pull request #94 from robertmaynard/better_travis_scripts

Better travis scripts