LG minor amendments and reformatting to LibRaw support.
Rename USE_RAW to USE_LIBRAW (and other similar renamings).
Add LIBRAW_PATH to allow a non-system custom LibRaw installation to be specified.
Expose USE_LIBRAW and LIBRAW_PATH to the Makefile wrapper.
Fix flash explanation if it's an int rather than uint
Beefed up raw metadata handling