Display transfers with the horizontal downscaling flag were calculating
the wrong output size, causing them to write double the amount of data
intended. It is likely that this was perceived as correct due to a
separate bug in calculating source indices which caused the image to be
padded unless the previous bug was present.

This fixes both issues, correcting flickering issues in 3dscraft,
blargSnes and more (caused by the transfer overwriting the back buffer
which followed) as well as potentially fixing other crashes.

The code was previously appending the interrupt to after the end of the
buffer, instead of at the end.

It appears this is a mistake, since the sub-screen has no right
framebuffer.

Hardware testing determined that the GSP processes shared memory
framebuffer update info even when no memory transfer or filling GX
commands are used. They are now updated on every interrupt, which isn't
confirmed correct but matches hardware behaviour more closely.

This also reverts the hack introduced in #404. It made a few games
behave better, but I believe it's incorrect and also breaks other games.

PDC0 and PDC1 are both VBlank interrupts. PDC0 was being treated as a
HBlank interrupt and fired many more times than it should. They now both
fire together at 60 Hz. This puzzlingly *improves* apparent framerate on
many applications.

A few other interrupts were being fired inside the GSP command
processing instead of on the actual GPU register writes, so they were
moved there, which should cover direct writes tho those registers not
going through the GX command queue.

Pica/Rasterizer: Add ETC1 texture decompression support.

Services: Added some missing services.

cfg:s, ptm:sysm, apt:s.
apt:s is almost exactly the same as apt:u as per 3dbrew

vfp: Remove dead code

Pica/VertexShader: Implement the MAD instruction.

Pica/VertexShader: Implement JMPC/JMPU/CALLC/CALLU.

dyncom: Fix 32-bit ASR shifts for immediates

dyncom: Remove unused flag macros

Qt Callstack: Clear the callstack every time it's updated

dyncom: Fix some more V-flag setting ops. Plus some cleanup.

Also cleans up CMN, and CMP.

This fixes the issue that old members of the callstack would stick around, even when the callstack shortened.

Fix MinGW build, again

dyncom: Fix ADC overflow flag setting

SVC: Wake up the thread after the delay in WaitSync1

dyncom: Fix conditional execution of MSR

Replace OnCpuStepped signal

Add appveyor.yml for AppVeyor support

Thread: Prevent waking a thread multiple times.

If a thread was woken up by something, cancel the wakeup timeout.