Added event.c/h and lua binding

* Changed mouse.c to mimic keyboard.c
* Changed boot.lua to use event.poll() instead of mouse/keyboard.poll()
* Removed love.keyboard.poll()

src/event.h

@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) 2016 rxi
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the MIT license. See LICENSE for details.
+ */
+
+#ifndef EVENT_H
+#define EVENT_H
+
+enum {
+  EVENT_NULL,
+  EVENT_KEYBOARD_PRESSED,
+  EVENT_KEYBOARD_RELEASED,
+  EVENT_KEYBOARD_TEXTINPUT,
+  EVENT_MOUSE_MOVED,
+  EVENT_MOUSE_PRESSED,
+  EVENT_MOUSE_RELEASED
+};
+
+typedef union {
+  int type;
+
+  struct {
+    int type;
+    int x, y;
+    int dx, dy;
+    int button;
+  } mouse;
+
+  struct {
+    int type;
+    const char *key;
+    char text[64];
+    int isrepeat;
+  } keyboard;
+
+} event_t;
+
+
+const char* event_typestr(int type);
+int event_poll(event_t *e);
+
+#endif