Unbreak display of IME text during composition

The text was not appearing when composing via the IME. It would not show
in the document until after the composition was complete.
Fix reselection of the eventTrap in IE11 & Firefox

Changing to an input element (1038583) affected how text ranges are
created in IE and Firefox. This stopped cut/paste from functioning.

setSelectionRange is supported on all major browsers.
Don't rely on boolean value being returned from DataTransfer.setData

According to the current specifications, this is a void return type.
Chrome is the only browser that returns a boolean value for this.

See http://www.whatwg.org/specs/web-apps/current-work/multipage/dnd.html#dom-datatransfer-setdata
Fix cut & copy in Internet Explorer

IE11 throws an exception when attempting to set an unsupported key such
as "text/plain". Could have done browser sniffing to detect IE instead,
but this approach seems equally valid.
Merge pull request #436 from peitschie/cut-ff

Fix cut & paste support for Firefox & IE