Move math modules to their own group

MetaballsKit/Math/Geometry.swift

@@ -0,0 +1,24 @@
+//
+//  Geometry.swift
+//  Metaballs
+//
+//  Created by Eryn Wells on 8/5/17.
+//  Copyright © 2017 Eryn Wells. All rights reserved.
+//
+
+import Foundation
+import simd
+
+public typealias Size = packed_uint2
+
+extension Size {
+    public init(size: CGSize) {
+        self.init(UInt32(size.width), UInt32(size.height))
+    }
+}
+
+extension Size: CustomStringConvertible {
+    public var description: String {
+        return "(\(x), \(y))"
+    }
+}