New version of pyexistdb released

We have released a new version of pyexistdb, the Python interface to the eXist-db database.

This is a minor update containing the following additions:

• Tells requests to ignore the `charset` property of the content-type field, and use the encoding passed to the `ExistDB` constructor. This is used to circumvent the bug described here.
  eXist-db version 4.2 was released, and it probably contains a fix to this bug, but `pyexistdb` may be used with older versions where the bug still exists.
• Add the ExistDB.retrieve_text method, in addition to the retrieve method. The retrieve method is supposed to return a string, but in some cases (when eXist-db uses base64 for encoding some of the data) it returns a binary stream. The new method  properly decodes this stream and always returns a string.
  We did not change the behavior of retrieve as it might break existing code.