Merge pull request #194 from zhaocai/master

Improve bookmark source : use * to glob ; _ to load all
- Fixed redraw_candidates().
- Fixed unite completion behavior.
- Fixed cursor move behavior.
- Fixed action initializer.
- Fixed <Plug>(unite_delete_backward_path)
- Added g:unite_force_overwrite_statusline option.
- Fixed cursor initialization.
- Fixed start sources behavior.
- Fixed unite#mappings#do_action().
- Fixed error.
- Major change to file_mru

1. Time to save:
- Before: Save to file on every event
- Now: Use VimLeavePre to save.

2. maintain two list, short one for quick start; long one for keep history.
use `file_mru:*` or `all`, `long`, `_`  to load.

3.