Menus can now have multiple versions of views thanks to :templates_path option for #build_mmmenu

Simply, provide a :templates_path option to #build_mmmenu helper like this:

    <%= build_mmmenu(@menu, templates_path: 'mmmenu/my_custom_menu') %>

Then you can put all the required template files in this directory and change them.
This is useful when you have various types of menus requiring different html-markup.
Fix: stub in a spec expected 1 call, but we needed 2
Fix: removing versions for rspec and bundler gems
Version bump to 0.5.1