citra-qt: static-constify a map.
BitField: Add an explicit Assign method.

This is useful when doing crazy stuff like inheriting from BitField.
Pica: Initial support for multitexturing.
citra-qt: Fix invalid memory read upon program startup.

This was caused by the framebuffer display widget not checking whether we are actually in a valid emulation state or not.
Pica/DebugUtils: Add support for RGBA8, RGBA5551, RGBA4 and A8 texture formats.
Pica: Implement texture wrapping.
Pica: Merge texture lookup logic for DebugUtils and Rasterizer.

This effectively adds support for a lot texture formats in the rasterizer.
Pica: Further improve Tev emulation.
Pica: Unify ugly address translation hacks.
Add support for a ridiculous number of texture formats.
Pica/CommandProcessor: Fix vertex decoding if multiple memory areas are accessed for different attributes.
Pica/CommandProcessor: Add a safety check for invalid (?) GPU configurations.
Pica/PrimitiveAssembly: Implement triangle strips.
Pica/DebugUtils: Add an event triggered after loading a vertex.
Add nihstro (a 3DS shader tools suite) as a submodule.
Pica/VertexShader: Remove (now) duplicated shader bytecode definitions in favor of nihstro's ones.
Pica/DebugUtils: Replace duplicated SHBIN structures in favor of nihstro's ones.
Pica/VertexShader: Support negating src2.
Pica/VertexShader: Some cleanups using std::array.
Pica/VertexShader: Move code around a bit.