We were applying the theme fonts taking only into account the
<a:latin>, <a:ea> and <a:cs> tags to set latin, eastAsia and cs fonts
respectively. Word uses in addition the <a:font> tags to define a
font name per language, in combination with <w:themeFontLang> tag in
settings.xml file which indicates the default language for latin, cs
and eastAsia. For example, with <w:themeFontLang w:bidi="he-IL" />
the default language for cs text is Hebrew, if the theme says
<a:font script="Hebr" typeface="Arial"/> then the selected font for
those sections of text should be Arial.

In theory, Word would also be able to define the language for a
specific section of text and that should receive the proper font from
the theme definition, but we are currently not supporting it. More
info: http://blogs.msdn.com/b/officeinteroperability/archive/2013/04/
22/office-open-xml-themes-schemes-and-fonts.aspx

Main changes in this patch:
* Added setter and getter values to ThemeTable and SettingsTable to
  be able to pass the values read in <w:themeFontLang> tag.
* Added support to manage the values in <w:themeFontLang> and
  <a:font> tags, which used to be discarded.
* Added methods to translate locale definitions to the language codes
  used in the <a:font>, using a table defined in the link above.

Change-Id: I78e6da5feab34cb9ff770a2c60e2f7229e7fb140