Added support for coveralls.io.
Changed Travis CMake configuration to enable coverage.
Ensured that gcov coverage can only be enabled when using GCC.
Changed Coveralls to exclude non-testing directories.
Ensure that we're using GCC before submitting to coveralls.
Added square braces around conditional.
Revert "Ensure that we're using GCC before submitting to coveralls."

This reverts commit 4725265e24dc0dadec03551b6c8ca1e124a86cc7.

Conflicts:
	.travis.yml
Merge pull request #39 from brennonbrimhall/master

Added support for coveralls.io.