Added mouse module (love.mouse), updated doc/files.md

src/mouse.h

@@ -0,0 +1,14 @@
+#ifndef MOUSE_H
+#define MOUSE_H
+
+enum {
+  MOUSE_BUTTON_LEFT,
+  MOUSE_BUTTON_RIGHT,
+  MOUSE_BUTTON_MIDDLE,
+  MOUSE_BUTTON_MAX,
+};
+
+void mouse_init(void);
+void mouse_update(void);
+
+#endif