Respect blinkOnRangeSelect when regaining caret focus

If blinkOnRangeSelect is false and the current cursor range is not
collapsed, the caret should NOT start blinking under any circumstances.
Merge pull request #305 from peitschie/blink-caret-issue

Respect blinkOnRangeSelect when regaining caret focus
Only make the event trap editable if the document is in edit mode

Various browser menus (cut, delete) should only enable if the document
is currently in edit mode.