Minor Dictionary changes

[mhavu]

Changed removeValueForKey(_:) to the current form removeValue(forKey:). Enabled the use of dot syntax in accessing key and value of a dictionary item. Added forEach as requested in issue #11.

[dwarfland]

Fwiw, this change does not build :(, I'll have to undo it

	public func forEach(_ body: ((key: Key, value: Value)) throws -> Void) rethrows {
		for item in self {
			try body(item) // E400 No overloaded constructor with 1 parameter for type "func (_ arg0: Key, _ arg1: Value)"
		}
	}

[mhavu]

Sorry about that. Looks as if I hadn't tried building this version at all. 🤦‍♂️ How come the compiler is looking for a constructor and not a function given as argument, though?