Avoid triggering SYNC ge signals.

Fixes #5806, bcause it avoids rescheduling at the signal, which it should
not do.  Possibly this is incorrect for all GE signals, but we don't need
to trigger any behavior on a sync anyway.
Don't trigger pause GE signals either, comments.

This better explains what each signal does.
Parse MP3 header to correct set the channel and samplerate
Merge pull request #5830 from raven02/patch-9

Parse MP3 header to correct set the channel and samplerate
Use ctx->mp3Channels instead of setting frame.channel in case of FF incomplete frame
Merge pull request #5831 from raven02/patch-10

Use ctx->mp3Channels instead of setting frame.channel in case of FF inco...
Cleanup comments again
Also show some important step from debug_log into info_log
Merge branch 'Mp4_branch' of https://github.com/kaienfr/ppsspp into Mp4_branch
Save current changes
still change logs
Win32: Properly shutdown when using File->Exit, or when g_Config.bEscapeExitsEmulator is true.
Texture lod bias should be signed
Merge pull request #5802 from raven02/patch-1

Texture lod bias should be signed
Merge pull request #5838 from thedax/win32BugFix

Win32: Properly shutdown when using File->Exit, or when g_Config.bEscapeExitsEmulator is true.
Update native with fix for #5832
Attempt buildfix for x86 cmake linux
Universal Audio Class
Based on my implementation in sceAac https://github.com/hrydgard/ppsspp/pull/5836
I've created a class AuCtx included in My SimpleAudioDec.cpp/.h which aims at providing a standard easy implementation to support all codecs in ffmpeg.
Here, I also completely re-code sceMp3 file with this class to give an example how to use this class, and it has solved all mp3 issues I've observed in the current master.
Tests on different freq and channels mp3 audios as:
Miku custom BGM (48kHz, stereo), Hanayaka Nari Wa ga Ichizoku(32kHz, mono, a little fast but better than before now), downstreet panic (44.1kHz, stereo), and learn jp09(44.1kHz, stero) are just all right.
Especially, I am very glad to see that Miku's Custom BGMs have no repetition issues in first tone any more and no longer stopped in the first second neither. :)
We will come into a new age to fast support new audio formats from now on I hope :P
Update minor comments
Merge remote-tracking branch 'origin/master' into Universal_Audio_Branch