* Clean up CMake logic
- removed logic to find CppUnit (no longer used)
- removed "dirs" variable used to pass include directories
- removed add_library function (no longer used)
- removed make_executable function
* only used in 2 places (polybar and polybar-msg)
* it was more general than needed, logic is simpler without it
- split polybar into static library and executable
* this allows linking unit tests to the library
* rename library
* add coverage build
- Added a CMake build type "Coverage" that builds C and C++
code with the "--coverage" flag (recognized by both GCC and Clang)
- removed "-Wno-missing-field-initializers" from test flags,
since it didn't seem to be needed any more
- removed logic from tests/CMakeLists to disable "-Werror" and "-pedantic-errors"
since there didn't seem to be any warnings during the build
* fix whitespace
* update travis
* remove O2 from defalt flags
* allow tests to be built by default make target
* disable Werror for debug builds
