Patch for font support and upgrade parseexel to ruby-spreadsheet

[Hugh McGowan]

Hi all,

I've got a patch for roo that adds some basic font support. This
currently supports testing cells for bold, italic and underline though
it could be extended to include more font information.

In the process of getting this to work I also updated roo to use ruby-
spreadsheet instead of parseexcel since the latter is no longer under
active development. While I was in there I also fixed the handling of
boolean true values as well as OpenOffice's handling of html-escaped
characters.

Documentation of the changes are here at http://wiki.github.com/hmcgowan/roo
and the main source is here: http://github.com/hmcgowan/roo/tree/master.

I've uploaded three files:
roo_fonts_lib.patch, roo_fonts_test.patch and oo_font_test_files.zip

Let me know if you have any problems with the patch or any questions.

Thanks!
Hugh