We just can no longer use the former ptr.getTypeName() as a fallback, but I do not suppose it matters. This value was an implementation defined string that usually contained a garbled mess.
Probably we should additionally refactor Lua types completely now that we have Ptr::getType(). I will leave this up to MWLua developers.
Currently, we use a peculiar mapping of ESM classes by their std::type_info::name. This mapping is an undefined behaviour because std::type_info::name is strictly implementation defined. It could return a non-unique value on some platforms. With this PR we use the unsigned int sRecordId of the ESM class as a more efficient lookup type that does not build on undefined behaviour. We can expect marginally faster save-game loading with these changes as well.
Return value can't be nullptr. Pointer complicates the code because has to be
dereferenced.
Also move function definition to hpp to make it easier for compiler to optimize
calls.
