fix(keypress): allow events to ommit key modifiers

Programmatically triggered events that do not include key modifiers (`altKey`, `shiftKey`, `ctrlKey`) properties would fail even when combination didn't require these keys.
chore(keypress): changed `|| false` per `git add modules/directives/keypress/` where possible
chore(keypress): test case events key modifiers are not defined by default
Merge pull request #486 from caiotoon/fix-keypress-custom-event

fix(keypress): allow events to ommit key modifiers