new internationalization support

FYI, I added some features related to internationalization to CSL. One
was the previously discussed date handling, and the second is related
to locators such as page numbers. Here’s an example of the first:

 <dates abbreviate-month-with=".">

<! – maybe should remove the above attribute and make people type in
punctuation?? -->

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

… and the second:

 <locators>
   <locator unit="page">
     <renderas>
       <single>p</single>
       <multiple>pp</multiple>
     </renderas>
   </locator>
   <locator unit="paragraph">
     <renderas>
       <single>¶</single>
       <multiple>¶¶</multiple>
     </renderas>
   </locator>
 </locators>

Comments?

I’m still mulling the possibility to switch back to attributes for
punctuation and such, so that I could do:

<name suffix=" ">Anonymous</name>

… where the content becomes the fallback. Need to think about whether
that’s a good idea some more.

Bruce