CMake: add missing headers to install target (3 files).
Merge pull request #224 from andioz/master

CMake: add missing headers to install target (3 files).
cmake: Make ctest run tests from EXECUTABLE_OUTPUT_DIR

This makes it possible to use it as a submodule in other projects,
that dont necessarily put exeutables directly under the build folder.
Merge pull request #226 from martiert/cmake-executable-output

cmake: Make ctest run tests from EXECUTABLE_OUTPUT_DIR