New tab key bindings

[outpaddling]

I just ported LilyTerm to FreeBSD. This is a very nice application, simple and clean, thanks for your work!
I'd like to suggest changing the default key bindings to Shift+Ctrl+letter rather than Ctrl+letter, as many terminal-based programs like text editors use control keys for their own functions. E.g. opening a new tab would be Shift+Ctrl+t instead of just Ctrl+t. Same for any other Ctrl+letter combinations. I don't think the Ctrl+function-key bindings are a problem, but others may correct me on that.