Minor API changes:

* You can now pass an "encoding" keyword argument
  into pragma_include.  This is now the only way
  to specify the encoding used to decode files
  loaded from disk by pragma_include.
* Removed the (undocumented) "encoding" attribute
  of the perky.Parser object.
* Removed the "encoding" parameter for loads.
* The "encoding" parameter for load is now only
  used by load itself when loading the top-level
  Perky file.