- added usage info
- added usage info

Original commit message from CVS:
- added usage info
- uses first arg as registry filename
- any additional args are plugins to search for (no change but argv base)
- cleaned up output with a spare \n

cablelabs/gstreamer,lubosz/gstreamer,lubosz/gstreamer,magcius/gstreamer,krieger-od/gstreamer,StreamUtils/gstreamer,collects/gstreamer,cfoch/gstreamer,krieger-od/gstreamer,ensonic/gstreamer,jpakkane/gstreamer,mparis/gstreamer,collects/gstreamer,krichter722/gstreamer,jpxiong/gstreamer,ensonic/gstreamer,krichter722/gstreamer,ylatuya/gstreamer,mparis/gstreamer,Distrotech/gstreamer,Lachann/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,jpxiong/gstreamer,cablelabs/gstreamer,drothlis/gstreamer,drothlis/gstreamer,Lachann/gstreamer,ylatuya/gstreamer,lubosz/gstreamer,drothlis/gstreamer,ahmedammar/platform_external_gst_gstreamer,krichter722/gstreamer,drothlis/gstreamer,justinjoy/gstreamer,lovebug356/gstreamer,ahmedammar/platform_external_gst_gstreamer,centricular/gstreamer,surround-io/gstreamer,jpxiong/gstreamer,Distrotech/gstreamer,StreamUtils/gstreamer,justinjoy/gstreamer,surround-io/gstreamer,cfoch/gstreamer,magcius/gstreamer,mrchapp/gstreamer,jpxiong/gstreamer,mrchapp/gstreamer,cfoch/gstreamer,Lachann/gstreamer,magcius/gstreamer,centricular/gstreamer,krieger-od/gstreamer,surround-io/gstreamer,ylatuya/gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,mparis/gstreamer,cfoch/gstreamer,krichter722/gstreamer,jpakkane/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,ahmedammar/platform_external_gst_gstreamer,centricular/gstreamer,ahmedammar/platform_external_gst_gstreamer,lubosz/gstreamer,mparis/gstreamer,jpxiong/gstreamer,Distrotech/gstreamer,justinjoy/gstreamer,justinjoy/gstreamer,ylatuya/gstreamer,Lachann/gstreamer,StreamUtils/gstreamer,lovebug356/gstreamer,ensonic/gstreamer,ahmedammar/platform_external_gst_gstreamer,Distrotech/gstreamer,mrchapp/gstreamer,lubosz/gstreamer,magcius/gstreamer,cablelabs/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,mrchapp/gstreamer,magcius/gstreamer,collects/gstreamer,mparis/gstreamer,collects/gstreamer,lovebug356/gstreamer,Lachann/gstreamer,krichter722/gstreamer,cablelabs/gstreamer,shelsonjava/gstreamer,surround-io/gstreamer,lovebug356/gstreamer,justinjoy/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,collects/gstreamer,drothlis/gstreamer,shelsonjava/gstreamer,krieger-od/gstreamer,ylatuya/gstreamer,StreamUtils/gstreamer,mrchapp/gstreamer,ensonic/gstreamer,Distrotech/gstreamer,StreamUtils/gstreamer,krieger-od/gstreamer,centricular/gstreamer,jpakkane/gstreamer