v3 is still a work in progress, and still fails some tests

* Replaced test data by data generated by a helper script (to make it
  easier to update)

* Use 'subtest' feature of unittest library in 3.4

* Small tweaks to plist library (the dump/load/dumps/loads function at
  the end probably won't survive)

* Updated link to the CFBinaryPlist.c source code (this should be a 
  newer version of the file)

* Added option to readPlist to pass in the dictionary type (defaults
  to plistlib._InternalDict). This is primarily useful for testing
  and debugging, but also mirrors the 'sortkeys' keyword argument for
  the writer (when the order can be important for writing the user should
  have some way to detect the order when reading).

The data generated by the binary plist generator does't match the data generated by Cocoa in OSX 10.8 (and generated by the helper script), I haven't fully debugged that problem yet.  The generated binary plist
and the Cocoa version can both be parsed by plistlib, and result in the same data structure