Revised CMake / Makefile install rules. For the Makefiles:
- make: installs in /usr/local (or whatever CMAKE_INSTALL_PREFIX says). This is the default. Normally would require "sudo make install"
- make local: installs in SuiteSparse/lib, ./include, ./bin (ignoring CMAKE_INSTALL_PREFIX)
- make global: same as "make", but can be done after "make local" to reset what "make install" does
- make both: installs in both places
These are handled by CMake options: -DGLOBAL_INSTALL=(true or false, 0 or 1), and -DLOCAL_INSTALL=(ditto). By default, GLOBAL_INSTALL is true (like "make global", install in CMAKE_INSTALL_PREFIX) and LOCAL_INSTALL (install in SuiteSparse/lib, SuiteSparse/include) is false.