Cleaned up escaping in xappSends. The xapp js code no longer escapes the name-value pairs sent
to the server - escaping is applied to these only by jQuery. The backend only needs to unescape
once and the previous code that handled a bug in mono has now been fixed in 3.2.0.

A word on the mono bug:
Previous, xappSend would effectively escape the data twice - once manually and once by
jQuery. On windows, the server side would unescape twice to cope with this but, for mono,
there was only a single unescape. This was because mono appeared to apply an unescape
somewhere in its guts - this is the bug that is fixed in v3.2.0.