Issue #99: generatekeyevent should send events to the system.

Sending keyboard events to the system is the best way of simulating user
interaction via keyboard. System is dispatching the evenets to the
focused application.

Sometimes focused application may not be the front most application.
Merge pull request #100 from mpichlin/issue-99/1

Issue #99: generatekeyevent should send events to the system.
fixup! Issue #99: generatekeyevent should send events to the system.

Keep API consistent.
Merge pull request #101 from mpichlin/issue-99/1

fixup! Issue #99: generatekeyevent should send events to the system.