add hardware decoding options

[mrgreywater]

Adds the option to change the decoder of the video to the QtAV and mpv backend. On my test machine with windows 10 and a Intel i5 3570k and a AMD graphics card the performance differences are quite drastic for a normal 1080p stream:

Cpu Usage:
qtmultimedia: 25%
mpv (dxva_copy): 10%
mpv (no): 25%
QtAV (DXVA zero-copy): 3%
QtAV (FFmpeg): 8% 

Artifacts: https://ci.appveyor.com/project/mrgreywater/orion

This commit also gives an option to start multiple instances, fixes some gui issues and reorders the player controls to a more similar order as youtube etc. I can potentially split those up into more commits or PRs as necessary.

edit: there are still some issues, will push a fix for some things soon

[alamminsalo]

I think the work done here is good but I'd rather see each feature/fix separated incase something needs to be reverted

[mrgreywater]

It appears some Intel graphics have issues with the default ANGLE opengl backend, so i need to add some option for that. After adding that i'll split the PR into multiple commits.

[alamminsalo]

Fuck it, these changes are great. No need to split up as the list changes were minor enough.

After this merge I will tag a new release

[alamminsalo]

Also, I think we should think of just removing the single/multi-instance features, as nowadays OS's handle that pretty good so that in most cases there's single instance running. The current filelock-instance handling has already caused some problems where user had to manually remove the instance because permission-issues. Users may then start multiple instances as they please

[mrgreywater]

I would also prefer just allowing users to start multiple instances to view streams side by side. There are a few things that may (not) work correctly though:

• Settings are not syncing at runtime
• the low latency proxy from here https://github.com/alamminsalo/orion/issues/243 won't work with a fixed port
• there will be multiple tray bar icons with no way to see which instance they belong too

Nothing of that is really problematic though, so just allowing multiple instances should be fine.

[alamminsalo]

Yeah, those are fair points.

I think traybar icon is currently really odd state as it has only features to show/hide application and quit the app. DE applicationbars most do that already and additionally can handle multiple windows too.

We would need to basically sync the settings via polling or something similar, and apply those in other clients. I'm unsure if this is going to be a big issue since settings doesn't have that drastic features.

I think we can solve the http-port problem (if I can understand the issue correctly), and in fact it would be good to know this early on (for the developers of low-latency support) so it can be taken into consideration

[mrgreywater]

I think this PR is ready.

There are still some unrelated issues with QtAV (see https://github.com/wang-bin/QtAV/issues/1149) which means we should pick a specific version in appveyor, and the OpenSSL in appveyor needs the msvc 2013 runtime, so it should probs be compiled in appveyor aswell.