SSP-2769 Change default HtmlEditor value to single-byte chars

Works around the problem described here (when you select text in the
Ext.js RTE, it prepends markup to the beginning of the doc; this
defeats code that tries to strip out a special char that is
normally inserted at the start of the document to make the
form field editable):

  http://www.sencha.com/forum/showthread.php?73293-FIXED-87-3.0RC3-HTMLEditor-prepends-to-message&p=572607&viewfull=1#post572607

This patch uses the fix described later in that thread:

  http://www.sencha.com/forum/showthread.php?73293-FIXED-87-3.0RC3-HTMLEditor-prepends-to-message&p=572631&viewfull=1#post572631