obs-gstreamer 0.4.0

• added option whether to clear the last frame on end-of-stream or error or not.
• added option to set retry timeout.
• changed macOS suffix from .dylib to .so to be actually picked up by OBS.

- Fixed some small bugs I think
- Accept RGBx and BGRx color formats
- Experimental prebuilt plugins

The prebuilt libraries are untested. If they don't work for you, please try to figure out why and report. I suspect there may be problems with dependency libraries to be found on the target system as they may be located on different ones as on the build machine..

- Add option to keep pipeline running when hidden

- fix video stride when row bytes are greater than width

• added option to set sinks to sync=false
• added option to restart pipeline after error
• clear data when pipeline not running (fixes freeze frame)