It appears that some older drivers do not support
CreateSwapChainForHwnd, resulting in DXGI_ERROR_INVALID_CALL. For these
cases, fall back to the base CreateSwapChain() from DXGI 1.0.
In theory this should also let us run on Win7 without the platform
update, but in reality we require the newer shader compiler so this
probably won't work regardless. Also any hardware of this vintage is
unlikely to run Dolphin well.
Greatly simplifies the overall interface when it comes to compiling
shaders. Also allows getting rid of a std::string overload of the same
name. Now std::string and const char* both go through the same function.
Stenzek