Introduce prefixes "etel", "mm" and "perf" for the etel removal, the devsound removal and the hardware floating point performance optimisations

Add --options argument to pass in the (comma separated lists of) prefixes for optional "What" commands For example, the use of vfp version of OpenVG could be indicated by "vfp_Stem", in which case the alteration will only be made if "--options vfp" is included on the filter_obyfile.pl command line.