Sprout 1.1

Improve sprout.saxext xmlimport and xmlexport classes:

• To make available user-defined options to the handlers. Those options have to be defined with the help of registerOption before being usuable.
• To support work on temporary files and already opened files. This is more efficient on large import and export, and prevent to create large StringIO objects.

Every piece of code using those classes will need to be updated to work with this new version.