We simplify hotkey mappings by using different hashes for
keydown and keypress events. There are browser bugs (iOS, for
example) where keypress events have the wrong keyCode values.
This led us, under iOS, to interpret "!" as "page up."
This fix also helps us disinguish escape from shift-escape.
Brock Whittaker helped on figuring out the keypress/keydown
issues that are addressed in this commit.
Fixes#4019
The initial version of the tests cover most normal keys, but they
do not cover special keys like enter/tab/escape or arrow keys
or home/end/page-down/page-up yet.
