Drop the hard-coded framework paths and "-framework JavaJM" on APPLE.

Save and restore the value of CMAKE_FIND_FRAMEWORK.  Use its value to
choose and order between a normal search for jvm&jawt and a framework
search for JavaVM.  When JAVA_HOME is set explicitly by the user then
force a normal search by setting CMAKE_FIND_FRAMEWORK to NEVER.  Once
the library is found, set CMAKE_FIND_FRAMEWORK to help find_path locate
the matching headers (framework v. normal).