upmc: Updates for building C modules w/base UPM

Test commit for building C UPM modules.

    * Added C include directory
    * Added C utilities directory
    * Rename C++ upm.h -> upm.hpp to make room for C upm.h
    * Added upm_mixed_module_init function to src/CMakeLists.txt.  This
      function takes filesnames similar to upm_module_init and does a
      bit of processing before calling upm_module_init.
    * Added c example directory.  Changed c++ example names.
    * Added dfrph implemention for testing (C++ wraps C).  Added mraa
      to .pc requires for dfrph.  Tested against stand-alone project.
      Added dfrph c example.
    * Update implemention of pkg-config file generation.
    * Added two cmake cache variables: BUILDCPP and BUILDFTI
    * Removed src from swig_add_module calls, added libname to
      swig_link_libraries calls.  Shrinks swig'ed binaries by ~13%.
    * Added install target in upm/CMakeLists.txt to install C header,
      directory.  Is this where we want this?
    * C FTI header directory is include/fti

Signed-off-by: Noel Eck <noel.eck@intel.com>

src/pkgconfig.in

@@ -3,11 +3,11 @@ exec_prefix=${prefix}
 libdir=${exec_prefix}/lib@LIB_SUFFIX@
 includedir=${prefix}/include
 
-Name: upm-@libname@
-Description: upm lib @libname@
+Name: @libprefix@@basename@
+Description: @libdescription@
 Version: @upm_VERSION_STRING@
 
-Libs: -L${libdir} -lupm-@libname@
+Libs: -L${libdir} -l@libprefix@@basename@
 Cflags: -I${includedir}/upm
 
 Requires: @reqlibname@