updated gitignore
Rename now return list of changed files.
Refactoring the multi-project stuff.
More refactoring of multi-project support.
Fixed PEP8 thing
Another .gitignore cleanup
Fixed relative-path calculation bug.

We now properly (I think) take symbolic links into account.
Factored out renaming tests.
Minor correct to cross-project tests.
Using new "common" module for combining tests.
rope-interface tests now using common test module.
Removed unneeded imports.