taglist: add warning when we get something else than a sample for a sample tag
taglist: add warning when we get something else than a sample for a sample tag

Facilitate GstBuffer -> GstSample transition for some tags,
could be hard to catch otherwise when creating tags, since
it'll only be apparent later when someone tries to read the
tags.

lubosz/gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,collects/gstreamer,mparis/gstreamer,collects/gstreamer,Lachann/gstreamer,mparis/gstreamer,lubosz/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,cfoch/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,justinjoy/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,jpxiong/gstreamer,krieger-od/gstreamer,Lachann/gstreamer,krichter722/gstreamer,collects/gstreamer,Lachann/gstreamer,krichter722/gstreamer,StreamUtils/gstreamer,lubosz/gstreamer,surround-io/gstreamer,lovebug356/gstreamer,jpxiong/gstreamer,collects/gstreamer,cablelabs/gstreamer,cfoch/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,justinjoy/gstreamer,mparis/gstreamer,Lachann/gstreamer,StreamUtils/gstreamer,jpakkane/gstreamer,cablelabs/gstreamer,jpxiong/gstreamer,lovebug356/gstreamer,ensonic/gstreamer,justinjoy/gstreamer,surround-io/gstreamer,Lachann/gstreamer,centricular/gstreamer,centricular/gstreamer,centricular/gstreamer,surround-io/gstreamer,krieger-od/gstreamer,lovebug356/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,jpakkane/gstreamer,krichter722/gstreamer,cablelabs/gstreamer,mparis/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,ensonic/gstreamer,krichter722/gstreamer,centricular/gstreamer,justinjoy/gstreamer,ensonic/gstreamer,collects/gstreamer,krieger-od/gstreamer,lubosz/gstreamer,ensonic/gstreamer,lovebug356/gstreamer,krieger-od/gstreamer,StreamUtils/gstreamer,krieger-od/gstreamer,StreamUtils/gstreamer,lubosz/gstreamer,krichter722/gstreamer,surround-io/gstreamer,surround-io/gstreamer