Renames the subdevice property to just device, and has it
return the number of devices in the system in response to
a probe. This is useful both for using multiple capture
cards, and for detecting whether it's worth adding the
element to a pipeline.
Also cleans up the property descriptions.
Builds with MSVC, not tested in MinGW or anything else. Added
COM handling code, borrowed from dshowvideosink. Moved Linux
specific files to ./linux and added Windows specific files to
./win (generated from IDL files in VS9). Added macros to handle
BSTR and defined bool as BOOL. Fixes#655362.
Signed-off-by: David Schleef <ds@schleef.org>
