Add GL_CLAMP_TO_BORDER support.

Travis: Remove use of sudo to enable use container-based builds

Update style rules with to better match current practice.

CMake: Fix Debug build configuration in MSVC

Common: Remove thunk.h

This isn't used, and there's no implementations of the member functions.

Cleanup includes, mostly in common

Debug was missing compiler flags, causing MSVC to default it to building
with optimizations enabled (making for a not very useful binary for
actual debugging...). Additionally, the variables were re-organized to
remove some redundancy, the old Release build type was removed, and
RelWithDebInfo was renamed to take its place instead.

Loader: Fix format specifier warning

AppVeyor: Remove submodule checkout depth

This avoid intermittent build failures due to a commit not being
reachable using a fixed depth, at the expense of longer checkout times.

Implement blended downscaling for display transfers

Services/SOC: Added command headers to some of the soc commands.

vfp: Change return type of VFPInit from unsigned int to void.

vfp: Handle accesses to FPINST/FPINST2 system registers.

Also has a side-benefit of correcting access to the FPEXC register.

Remove unused type unions breaking aliasing rules in horrible ways