Merge pull request #1276 from ricksladkey/fixes-backspace

Full support for 'backspace' option
Merge pull request #1287 from ricksladkey/fixes-select-after-disabled

Handle active selection after being disabled
Merge remote-tracking branch 'upstream/master'
Add support for 'selectmode=cmd' setting

- Map normal mode 'v', 'V', 'C-v' and 'C-q' to new SwitchModeVisualCommand
- Implement SwitchModeVisualCommand to obey 'selectmode=cmd'
- Add unit tests to verify 'selectmode=cmd' behavior
Merge branch 'fixes-selectmode-cmd'
Fix regression in dragging to start visual mode

- Add new IsMouseKey predicate
- Don't handle unmatched mouse keys in visual mode
Merge branch 'fixes-visual-mouse'