New fork of tray project incorporating many useful fixes

[dmikushin]

Hello, as @zserge is probably not actively maintaining this repo anymore, I would like to offer a fork, which brings together the great original code by @zserge and the most interesting forks and PRs of their respectable contributors:

• Only process messages coming from the tray window on Windows
• Become C++-friendly
• Fix all menu items have a check box
• Add support for tooltip
• Darwin implementation translated from C to Objective C adapted from @trevex fork
• Moved from Makefile to CMake, based on @LonghronShen fork

[rubyFeedback]

dmikushin are you still active? cody offered to add this to libui-ng so this may be implemented/added eventually.

[LonghronShen]

Can't agree more.

[dmikushin]

@rubyFeedback Sure, this is a great idea!