Pica/CommandProcessor: Fix vertex decoding if multiple memory areas are accessed for different attributes.

This effectively adds support for a lot texture formats in the rasterizer.

- Linear simply indicates that the mapped physical address is always MappedVAddr+0x0C000000, thus this memory can be used for hardware devices' DMA (such as the GPU).

The affected code is no longer limited by compiler support on that platform.

Double-clicking a texture parameter command in the pica command lists will spawn these as a new tab in the pica command list dock area.

The texture viewer is enabled when selecting a write command to one of the texture config registers.

The view is scaled to be as large as possible, without changing the aspect, within the bounds of the window.
On "retina" displays, or other displays where window units != pixels, the view should no longer draw incorrectly.

This was automated using `clang-modernize`.

This prevents a crash when the buffer size returned by the driver is 0,
in which case no space is allocated to store even the NULL byte and
glGetShaderInfoLog errors out.

Thanks to @Relys for the bug report.