Rae Kim

If g:osc52_term is not set, it will be always considered as tmux. Fix 1. Use g:osc52_term first 2. Fallback to auto-detection if g:osc52_term is not set or set to unsupported...

**Is your feature request related to a problem? Please describe.** It would be nice if a gui window can switch mux window it displays. I know there is workspace. But...