[DSHOW-13] Fix IGraphBuilder::ConnectDirect

[Robert Shearman]

Hi,

Keeping this patch small because of superstition and all that :)

Note: the second item in the change log should have been included in
DSHOW-12, but I forgot about it. It won't harm to merge these patches at
different times, but people with no-windows installs won't be able to
register DevEnum without this fix.

Rob

Changelog:
- Fix IGraphBuilder::ConnectDirect
- Register IFilterMapper and IFilterMapper2 in DllRegisterServer