Support Python 3

Thanks for pointing this problem out. Adding the "u(...)"-function would not be a big deal and I'll happily do it, since the scripts would then run on python 2 and 3. However, I did some quick tests with the 2to3 tool and there are at least two other constructs that are quite frequently used that would need to be replaced:

- if node.attrib.has_key("{" + inkex.NSS["jessyink"] + "}view"):
+ if "{" + inkex.NSS["jessyink"] + "}view" in node.attrib:

- for id, node in self.selected.items():
+ for id, node in list(self.selected.items()):

Do you know whether the suggested changed still work in python 2?

According to the documentation, both changes do work in every Python 2 version (http://docs.python.org/release/2.0)

A somewhat problematic change would be for example the exception handling, which leads to incompatibilities between <2.6 and >=3.0. Python 3 only allows "except Exception as e:", but the keyword "as" does not exist in <2.6.
Fortunately, I could not find deprecated constructs like "except Exception, e:" in JessyInk, so this is *currently* no problem.

Another hint for the u(...) function: instead of try/except, it is also possible to use sys.hexversion or sys.version_info.

Thanks for checking that out. I'll try and fix the scripts so they run on python 2 and 3.