CMake polishing

* Improve CPU features detection

  CMAKE_SYSTEM_PROCESSOR is pretty useless (e.g. when compiling with
  MSVC ARM64 toolchain and Ninja still returns system processor).

* Don't build src/utils targets by default

  Fix compilation for UWP platform.

* Add more Visual studio Git ignore patterns
* Autogenerate Doxygen docs

Makefile.am

@@ -43,6 +43,8 @@ EXTRA_DIST = \
 	flac-config.cmake.in \
 	cmake/FindOgg.cmake \
 	cmake/UseSystemExtensions.cmake \
+	cmake/CheckCPUArch.cmake \
+	cmake/CheckCPUArch.c.in \
 	COPYING.FDL \
 	COPYING.GPL \
 	COPYING.LGPL \