Removed implicit cast from fun type to return void in type inference (this is done in the codegen now)
Error when sending a closure to C
Simpler code to implicitly cast a String to UInt8* for interfacing with C
Simpler code to implicitly cast nil to pointer to function pointer for interfacing with C
Fixed: was able to invoke `Foo.new` if Foo only had `self.new(x)`
Allow fun literal with C enum types as arguments
Allow specifying a C enum's base type