Revert "DSound: use DSound notifications to produce sound."

This reverts commit 4990b8910bc0fe5d576f92396f761a79b3f1a7e3.

The commit is causing substantial performance issues for the DSound
backend which I somehow didn't catch during testing.
Video backends: remove dead code.
Fix the capitalization of "GameCube" throughout the project.
BitField: Delete copy assignment to prevent obscure bugs.
Fix a few warnings caused by using BitField with non-typesafe functions.
BitField: Add an explicit getter function for retrieving the BitField value.

Sometimes (in particular when using non-typesafe functions) it can be convenient to have a getter method rather than performing a potentially lengthy explicit cast.
Fix conditional branching on x86_64.
The register cache can be filled to the point that when dumping them the FixupBranch goes over the maximum size of 0x80.
Force them to use the "5byte" variant of the jump.

If we were able to determine if the length we had to jump was <0x80 in the future this could be a slight optimization.
This has to be done in bcctrx, bclrx, and twx. It was already done in bcx before.
This fixes issue 7378.
Merge pull request #487 from Sonicadvance1/Fix-Conditional-branch

Fix conditional branching on x86_64.
Fix the vertexloader on non-x86 targets.

When I dropped ARM from a generic target, this caused the vertexloader to try using the JIT path.
Instead of !_M_GENERIC, check for _M_X86 instead. Since it is only for the x86 target
Merge pull request #489 from Sonicadvance1/Fix-NonX86

Fix the vertexloader on non-x86 targets.
Merge pull request #483 from neobrain/bitfield_fixes

BitField fixes
Merge pull request #470 from pauldacheez/s-Gamecube-GameCube

Fix the capitalization of "GameCube" throughout the project.
Merge pull request #440 from magumagu/dsound-revert

Revert "DSound: use DSound notifications to produce sound."
Merge pull request #445 from magumagu/video-dead-code

Video backends: remove dead code.