Use more verbose/descriptive names for the "public API" functions in the ExternalProject.cmake module. Follow the cmake function naming convention, using a ModuleFileName_ prefix. Locate stamp files under a CMAKE_CFG_INTDIR subdir of the stamp dir so that debug and release builds have separate stamp files for Visual Studio builds. If no CMAKE_GENERATOR argument is given to ExternalProject_Add, default to using the parent project's cmake generator.