A bunch of changes I did while working with grandalf.

Changes:

- Use izip and xrange when possible.
- Added a route_with_ronuded_corners (which creates routing with rounder corners).
- Updated tests to run with pytest (note that test_recurs() is failing -- but it was already failing before).
- Created a few helpers at utils.
- Changed print to print() -- for python 3 (but should still work on python 2).
- Fixed a divide by zero issue (grandalf\layouts.py:784: RuntimeWarning: divide by zero encountered in double_scalars).
- Dealing properly when reading utf-8.
- Removed a potential halting issue (mypdb.set_trace() leftover).
- Right-trimmed some lines (IDE did it automatically: sorry for this noise, hope it's OK).
- Added .pyc to .gitignore.
- Added some helper files to make it easier to load project on PyDev.