Add feature to detect device's remove/insert events.
Description
Add feature to detect device's remove/insert events. When device is inserted, win-dshow can restore camera when received event. However, to be enable to detect remove/insert, we must success to initialize dshow firstly. Besides, it seems insert/remove events won't be sent for audio filter.
Motivation and Context
Help win-dshow to restore camera when device is inserted.
How Has This Been Tested?
Tested on Window10 with Legitech C920
Types of changes
New feature (non-breaking change which adds functionality)
Checklist:
- [x] My code has been run through clang-format.
- [x] I have read the contributing document.
- [x] My code is not on the master branch.
- [x] The code has been tested.
- [x] All commit messages are properly formatted and commits squashed where appropriate.
- [x] I have included updates to all appropriate documentation.
After merging this PR, we can improve win-dshow to restore camera automatically:

@jp9000 Request your review
This will not be reviewed until some time after v27 is released.
This will not be reviewed until some time after v27 is released.
Got it!
Hmm~ will this PR be merged ?
sorry about that, I'll try to get around to it sooner than later, it's just easy for things to slide (especially when they're on repositories other than the main repository)