Follow up on ZK-676

If tooltiptext attribute is binded in a zul to an HTML string, HTML get's escaped with $amp;gt;, <, etc.
If, however, it's set on runtime, it get's displayed correctly.

Say string is like this: foobar"><script>alert("Hi!")</script><!--

If tooltiptext is binded to it, it get's rendered as
foobar&quot;&gt;&lt;script&gt;alert(&quot;Hi!&quot;)&lt;/script&gt;&lt;!--

If it's set on runtime, this is the result:
foobar"><script>alert("Hi!")</script><!--

Preferably, it should always be the latter result.