a) remove special handling of 0x0002 in our custom icu rules.
   Which brings us a step closer to getting rid of at least
   some of them in favour of the defaults
b) expand the 0x02 in SwTxtNode::BuildConversionMap like we
   do for fields so

Good side effect is our word count and character count now take into account
the actual footnote indicator text, as does our cursor travelling. Both of
which are more word-alike.

Change-Id: I3b0024ac4b10934bee7a9e83b0fce08a18556c7b