Allow the following:

	contract A {
		// Take raw calldata as argument and return return data
		fallback(bytes calldata input) external payable (bytes memory) {}
	}

Allow a function to be called fallback:

	contract A {
		// Will give a warning that's not a fallback function,
		// just a regular functon
		function fallback() public {}
	}

Signed-off-by: Sean Young <sean@mess.org>