trigger custom "menuToggle" event when menubutton is clicked

trigger an event called "menuToggle" when the mobile menubutton is clicked,
which gives us the possibility to add custom behavior to some elements when the menu opens or closes.
add slide-div to template and change how javascript adds the menu to the template

added slide-div to the template that will be replaced by javascript,
which gives us the  possibility to place that div anywhere in its template and place content before and after it.
Merge pull request #226 from mike-tuxedo/mobile-menu-improvements

Mobile menu improvements