normalize itext when rendering xform

http://manage.dimagi.com/default.asp?97349
Convert this:
```
    id1: en => 'yes', sp => 'si'
    id2: en => 'yes', sp => 'si'
    id3: en => 'if', sp => 'si'
```
to this:
```
    id1: en => 'yes', sp => 'si'
    id3: en => 'if', sp => 'si'
```
and rename the appropriate label references in the form.