Update zenburn color scheme
Merge branch 'update-zenburn-cs'

Update zenburn color scheme (by Svyatoslav Mishyn, a.k.a. juef).
Version v0.7.7
Merge branch 'release-0.7.7'

vifm v0.7.7 release

New version provides more customizations for several existing features
and more convenient interaction with them.

Thanks to all contributors and especially those who tried beta version.

Main changes:

 - Vifm has had support for navigation by file number for years, finally it
   can display those numbers.

 - Support of trash directories got better with ability to have trash per
   mount point and new trash menus.

 - Command-line mode now has Ctrl-X prefixed keys that insert parts of
   filenames and filters (kind of Ctrl-R in Vim).

 - Bookmarks are now timestamped for more predictable management (mainly
   deletion and overwriting).

 - For security reasons remote commands are now disabled at configuration
   stage by default.

 - Most of long-running operations (:find, :copy, etc.) now can be cancelled
   by pressing Ctrl-C.

 - Menus with list of files got unified "gf" (for navigation) and "e" (for
   editing) shortcuts.

 - Several fixes and %n macro for better integration with terminal
   multiplexers.

 - Ability to sort list view with disabled grouping of directories.

 - Expression parser was extended in a couple of ways.

 - Added three more sample color schemes.