OpenGL: Improve accuracy of quaternion interpolation

Dependencies and build system cleanup

Modules didn't correctly define their dependencies before, which relied
on the frontends implicitly including every module for linking to
succeed.

Also changed every target_link_libraries call to specify visibility of
dependencies to avoid leaking definitions to dependents when not
necessary.

video_core didn't even properly use them, and they were the source of
many otherwise-unnecessary dependencies from core to video_core.

This removes a dependency inversion between core and common. It's also
the proper place for the file since it makes screen layout decisions
specific to the 3DS.

Add the fmt string formatting library

More info at http://fmtlib.net/

This commit was based on @jroweboy's work on his spdlog branch, but with
modifications.

Updated to incorporate fix from MerryMage/dynarmic#106 which is required
for using fmt in Citra.

gl_shader: refactor texture sampler into its own function

Current order of operations (rotate then normalize) seems to produce a
lot more distortion than normalizing and then rotating. This makes Citra
results match pretty closesly with hardware, and indicates that hardware
may also be using lerp instead of slerp to interpolate the quaternions.

Decentralize ResultCode

Implemented Procedural Texture (Texture Unit 3)

It is now known that result code description vary depending on the
module, and so they're best defined on a per-module basis. To support
this, allow passing in an arbitrary integer instead of limiting to the
ones in the ErrorDescription enum. These will be gradually migrated to
their individual users, but a few will be kept as "common" codes shared
by all modules.

Telemetry framework Part 1

Dyncom/VFP: Convert denormal outputs into 0 when the FTZ flag is enabled.

Kernel: Properly update port counters on session disconnection.

It is not meant to be used by anything other than CreateSessionPair.

Dyncom/VFP: Perform flush-to-zero on the second operand of vsub before sending it to vadd.

externals: Update catch to 1.9.4

Upgrade AppVeyor to Visual Studio 2017

The file does not seem to exist anymore in the VS 2017 environment.

More C++14/17 goodness!

swrasterizer: add missing tc0_w attribute processing