ENH: Improved support for user-configured search paths. Paths given in the...

ENH: Improved support for user-configured search paths.  Paths given in the CMAKE_LIBRARY_PATH cmake variable are searched first, then those in the CMAKE_LIBRARY_PATH environment variable, then those listed in the call to the FIND_LIBRARY command and finally those listed in the PATH environment variable.  The support is similar for finding include files with FIND_PATH, but the variable is CMAKE_INCLUDE_PATH.