Add Setting panel

Signed-off-by: onevcat <onevcat@gmail.com>
Merge branch 'master' of github.com:onevcat/VVDocumenter-Xcode into setting-panel
Add space and customize trigger string.

Signed-off-by: onevcat <onevcat@gmail.com>
Update README

Signed-off-by: onevcat <onevcat@gmail.com>