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.
Depending on which constructor is invoked, m_id or m_compute_program_id
can end up in an uninitialized state. We should ensure that the object
is completely initialized to something deterministic regardless of the
constructor taken.