Fixed jquery import in questionset.html (the path did not match the actual file).
Added custom field to the question type dropdown list in Django Admin.
The range Javascript is included only for RANGE field type.

After the number field was added, it was included for both RANGE and NUMBER fields.
It is possible to define initial values of tags in the take/1 GET request.

E.g. of use: "take/1?tags=tag1,tag2".
It could be useful if you have two versions of the same questionnaire,
normal and extended, and you want to control the version using the GET
parameters.
Added Polish translation to i18n.
Fixed and changed the "Same as Another Question field".

This field didn't work, because there were check parse errors.
Currently, to use this field, you need to put "sameas=question.id"
in the checks field. We used the question id in order to be able
to use this functionality between different questionnaires.