vfp: Normalize accumulator for multiply accumulate instructions

dyncom: Add more regs to MCR/MRC

Adds the registers that were left out of some coprocessor ranges.

Add more blend equations from 3dbrew

Scheduler refactor Pt. 1

* Simplifies scheduling logic, specifically regarding thread status. It should be much clearer which statuses are valid
for a thread at any given point in the system.
* Removes dead code from thread.cpp.
* Moves the implementation of resetting a ThreadContext to the corresponding core's implementation.

Other changes:
* Fixed comments in arm interfaces.
* Updated comments in thread.cpp
* Removed confusing, useless, functions like MakeReady() and ChangeStatus() from thread.cpp.
* Removed stack_size from Thread. In the CTR kernel, the thread's stack would be allocated before thread creation.

Mutex/synch fixes

vfpdouble: Fix the FTOUI NaN sign setting

This was fixed for vfpsingle, but not vfpdouble

Throw more unused/unnecessary VFP code out

Cleanup related to vfp_helper.

Appveyor: Do x64 builds

The submodule update was doing a full clone. Also increase clone depth a
bit, since it can apparently cause issues checking out the source if
there are too many concurrent PRs trying to build (causing the commit
for the build to not be the top one on the repository anymore).

Fix a wrong file name in a comment

Small VFP cleanups.

Also got rid of duplicate definitions of some of these values.

Implement color/alpha modifiers

vfp: Fix VCVT

vfp: Throw out unused code

These variants exclusively read from the single precision regs and write to double-precision registers
Fixes issues where converted values would be way off from what they should be due to the results being stored in the wrong registers.

Disassembler improvements

citra-qt: Fix horrible scrolling responsiveness in disassembler by giving the uniformRowHeight hint.

dyncom: Remove more unnecessary code