add :quit key to uninstall

The applescript is divided into two commands to keep from transiently
invoking the application in the case where it is not currently running.
quit keyremap4macbook on uninstall

before attempting to unload kext and delete files
validate keys given to :uninstall

this should also be part of audit
add :quit key to uninstall check
Merge pull request #2018 from rolandwalker/uninstall_quit

Uninstall quit
Merge pull request #2019 from rolandwalker/validate_uninstall_keys

validate keys given to :uninstall
cut v0.24.0
Update changelog