* Fixed issue-1131 (do not show files in MRU lists which do no longer exist)
The solution consists of an extension of the Action system allowing to
dynamically hide or disable items. This currently works for menu items only.
This feature is used to dynamically *disable* (as of now, not hiding)
items from the four MRU lists corresponding to non-existing files.
In addition, a "clear list" menu has been added to the MRU lists.
* Small enhancement: file names can be URIs
New convenience functions are provided which simplify
manipulation of key bindings and menu item visibility
configuration strings. AbstractMenu#pack_key_binding
and AbstractMenu#unpack_key_binding turn a path/key
map into a single string and back. The string format
is the same than for the key-binding configuration key.
The same is provided for the menu item visibilily
with AbstractMenu#pack_menu_item_visible and
Abstract#unpack_menu_item_visible.
In the setup dialog (Customize Menu page), there are check boxes
now by which menu entries and menus can be enabled or disabled.
CAUTION: don't disable the setup function :-)
- Include a copy of the unit test framework so we're no longer
depending on incompatible versions for Ruby 1 and 2.
- Avoid duplication of path entries in unit tests