Make accidentals in figured bass use the normal fontsize

[pnorcks]

http://codereview.appspot.com/74056/diff/1/2
File scm/translation-functions.scm (right):

http://codereview.appspot.com/74056/diff/1/2#newcode109
Line 109: #:general-align Y DOWN
The accidentals look nicer now, but this breaks the alignment for the
figured bass continuation lines and numbers.  See the regtest
figured-bass-continuation-center.ly.

IMO, the double-sharp looks a *lot* nicer when the font size is +2, so I
would add that back.  See the regtest
figured-bass-continuation-modifiers.ly

http://codereview.appspot.com/74056