Added a bit of code to make new version compatible with v0.1.1's config
file (in preparation for pushing the new gem). This should make it less
infuriating for users who download the new version and haven't (or don't
want to) run "redmine install".
Fixed some bugs in the edit command:
  - Now, if you don't actually make a change to a value, it won't be
    submitted.
  - Some extra logic prevents updates without any new data from being
    submitted as well.