Create macro for making libraries.

Also, use the Cotire CMake package to optionally speed up builds using
precompiled headers.
[travis] Use precompiled headers on travis.
Remove cotire cmake module (for now). It showed no speed-up on travis.
[travis] Remove cotire.
[cmake] Correct typo in author name.
[cmake] Clean up authors string.
[cmake] Clean up authors string.
[cmake] Clean up authors string.
Merge pull request #201 from chrisdembia/cmake-macro

CMake macro for building libraries