Fixes and additions

[TeeVahReeeeeen]

A few changes to make in2lambda work for the updated Lambda Feedback and also make it easier to use:

• The minimum template now matches that on the current version of Lambda Feedback, which in turn means worked solutions are correctly imported
• it now generates a single set.zip file that you can import into Lambda Feedback in one go, rather than having to do each question one at a time
• Added support for .docx files (though it is currently a bit of a workaround. I couldn't find an elegant solution, but may come back to it. From a user perspective it functions the same).