Hotfixes and documentation updates

[Avasam]

Hotfixes and documentation updates following the 2.0.0 release.

Everything here should be considered a "patch" update and can go in 2.0.1

• Fix DesktopDuplicationCaptureMethod error because it's missing a parameter in __init__ (Fixes 2.0 D3D Desktop Duplication unhandled exception #229)
  • Made CaptureMethodBase non-optional to help type-checking catch these cases
• Fix somewhat inconsistent BitBlt error when closing a dolphin game (but not the emulator itself)
• Fix pHash returning a match of 0 upon a perfect match
• Fixed an issue where AutoSplit would automatically restart if Loop Last Split Image to First Split Image was checked and AutoSplit was manually "stopped/reset".
• Make the autostart image comparison timer and the live preview refresh timer respect FPS limit setting changes
• Optimize the live preview by re-using the image from comparison instead or requesting another new image
• Fixed some numbers being rounded up in the GUI instead of being truncated. (a 0.996 match was incorrectly displayed as a perfect 1.00 match)
• Support Dummy Flag for start image (Fixes Auto Start: Support dummy flag #222)
• Better handle some camera errors
  • Will now let the error though but display a blank frame for Capture Card not being available or not supported by OpenCV.(Closes Take Screenshot creates image with wrong resolution #58 , relates to Capture card throws (-2:Unspecified error) could not retrieve channel 0 in function 'cv::VideoCapture::retrieve' opencv/opencv#23539)
  • Hide OBS Virtual Camera to prevent confusion with the plugin and prevent AutoSplit crash when selected.
• Moved documentation in docs
• Added docs/CONTRIBUTING.md