Add frequently used key combinations

I'm in the process of adding a few key combos:

~~- [ ] ^A, ^E, ^K, ^D~~
- [x] ^H - delete character before cursor

I'm going to keep pushing to this branch and opening pull-requests (if this one is not still open.) 

@garybernhardt if you're not interested in these let me know and I won't bother with the pull-requests. Thanks!