Fixed sublime plugin behaviors.

- Fixed subl search path order in Mac because Sublime Text 3 is named
  Sublime Text.app by default instead of Sublime Text 3.app and they are
  mostly likely to be placed in /Applications instead of
  $HOME/Applications.
- Fixed sublime text binary path in Linux. The sublime_text binary
  installed by Ubuntu installer is placed in /opt/sublime_text/sublime_text
  instead of /usr/bin/sublime_text.
- Use zsh's built-in process detach syntax instead of nohup.
Integrate changes from #1841.
Merge pull request #2572 from kevinxucs/sublime-linux-fix

Fixed sublime plugin behaviors.