Now that we utilize C++17, we can simply return an optional containing
the code instead of using an out variable and a boolean result,
essentially combining them into one.
This provides a much more straightforward interface.
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.
Lioncash