Cleanup modules intended to be merged in CMake

Rename:
  MacroUninstallTarget.cmake -> AddUninstallTarget.cmake
  MacroExtractVersion.cmake -> ExtractVersion.cmake
  MacroStandardFindModule.cmake StandardFindModule.cmake

Also update AddUninstallTarget.cmake from CMake wiki, remove deprecated
stuff and comments, clean documentation and prepare for inclusion in
CMake, and relicense to 3 clause BSD.