DShowPlayer improvements

Currently, DShowPlayer has a lot of hard-coded decisions in it, that may not necessarily be required with newer filters out in the wild (and potentially being rolled into the sagetv product). Things like VideoRenderer being limited to specific choices, some media formats being forced to use specific filters in code instead of using properties, etc. Basically, with the newer decoders and renderers available, which have much greater capability, it might make sense to open up these restrictions and allow any option to be selected for each container/format/renderer.