Loads settings after the plugin is loaded. (Fix for ST 3)

In Sublime Text 3, plugins must load their settings after they have been loaded themselves. Therefore, it is necessary to trigger load_settings() in the plugin_loaded() function. This commit fixes the problem and makes SublimeLaTeXWordCount work in ST3 again (it did not work for me before this fix).

See also: http://www.sublimetext.com/forum/viewtopic.php?f=6&t=15160