re #589 - adding main menu to page template in springboard_base and removing in springboard_frontend. overriding menu-related theme functions to use Bootstrap classes
re #582 - overriding main menu settings to always use springboard_admin_menu as main menu in springboard_backend theme
Merge branch '7.x-4.x' of https://github.com/JacksonRiver/springboard-themes into 7.x-4.x