ecore: Add a new API function ecore_main_loop_nested_get

Summary: This commit adds a new function 'ecore_main_loop_nested_get'
so that we can detect if the ecore_main_loop is running.

NB: This is going to be needed for a new eldbus function that we have
to add in order to handle a use-case on the Wayland side. Spoke with
cedric for a while wrt to all this, and he gave it his 'ok' ;)

@feature

Signed-off-by: Chris Michael <cp.michael@samsung.com>

src/lib/ecore/Ecore_Common.h

@@ -280,6 +280,16 @@ EAPI void ecore_main_loop_quit(void);
  */
 EAPI Eina_Bool ecore_main_loop_animator_ticked_get(void);
 
+/**
+ * Returns if the ecore_main_loop is running
+ * 
+ * @return an integer specifying if the ecore_main_loop is running,
+ *         0 if not running, > 0 if running
+ * 
+ * @since 1.3
+ */
+EAPI int ecore_main_loop_nested_get(void);
+
 /**
  * @typedef Ecore_Cb Ecore_Cb
  * A generic callback called as a hook when a certain point in