Issue #2774619 by stevetweeddale: Add block, link context variables to template_preprocess_menu_attach_block_wrapper()

Issue #2270465 by kyletaylored, cam8001: Notice: Undefined index: use_ajax in menu_attach_block_link() (line 155 of menu_attach_block.module)

Issue 1693282: Removed css class from links that previously had an attached block but don't anymore.

Issue #1673110: Fixed incompatiblity with menu_attributes.module (or any other module that alters menu_edit_item $form[options]).

[#1583524] Added backend configuration for horizontal/vertical block attachment option. CSS and JS to come.