Incremental release

This is a fairly major non-breaking change:

Functionality:

• Added IncludeSize function, that gives an indication which includes cause your compiler the most grief.
• Use CMake for the build instead of Makefiles / VS project files.
• Enable use of std::filesystem, if you have a compiler that has it.

Speed:

• More accurate and faster parsing logic.
• Now using Trajan's algorithm for finding cycles, which makes the cycle analysis much faster. Saves 20% on total runtime on my test target.
• Enabled use of mmap for reading files.

Code quality:

• Fixed various bugs, all resulting in crashes in case of misuse.
• Fix issues found by PVS-Studio. 19 minors and one critical.
• Add Appveyor build & Travis build with unit tests, running on Linux, Mac and Windows.
• Switch testing to simple test framework, to avoid gtest's use troubles on Travis and Appveyor.

Initial release

Initial release with all functionality existing and working well for Linux and OSX systems, but known problems on Windows.