Improve description of NONE mode in "CMAKE_FIND_ROOT_PATH_MODE" documentation
The sentences "If set to ONLY, then only the roots in CMAKE_FIND_ROOT_PATH will be searched." should be augmented with:
"Note that cmake will ignore paths in the cmake specific variables CMAKE_PREFIX_PATH, CMAKE_LIBRAY_PATH, CMAKE_FRAMEWORK_PATH when mode is ONLY".
Additionally, a new mode should be provided (ONLY-EXPLICIT) in which the cmake specific variables are not ignored.
Edited by Stephen Webb