Better name matching

[L3tum]

This wasn't done before because of performance concerns, but it's Python so it's gonna suck anways.

• Mangle names
• Every Functiona and Struct has a "canonical name"
• This name is checked instead of the mangled name
• Following that the arguments (in case of functions) is checked whether they match up
• Everything else still applies (no function -> error, multiple functions -> error)