Updated examples for Python 3 compatibility

I updated a variety of examples to make them work with Python 3. Most fixes were pretty straightforward (adding parenthesis to print, wrapping dict and map in lists as they return iterators in Python 3).

Link to original issue
https://github.com/scikit-learn/scikit-learn/issues/2815#issuecomment-33905566

I ran the tests (nosetests-3.3 --exe sklearn) and I got one error, which seems unrelated to the examples I edited. **Could you please verify this?**

Traceback:

```python
FAIL: sklearn.linear_model.tests.test_least_angle.test_lasso_lars_vs_lasso_cd_ill_conditioned
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/local/lib/python3.3/site-packages/nose/case.py", line 198, in runTest
    self.test(*self.arg)
  File "/Users/hendrikheuer/Projects/scikit-learn/sklearn/linear_model/tests/test_least_angle.py", line 327, in test_lasso_lars_vs_lasso_cd_ill_conditioned
    linear_model.lars_path, X, y, method='lasso')
  File "/Users/hendrikheuer/Projects/scikit-learn/sklearn/utils/testing.py", line 189, in assert_warns_message
    % (func.__name__, warning_class, w[0]))
nose.proxy.AssertionError: First warning for lars_path is not a <class 'UserWarning'>( is {message : DeprecationWarning('converting an array with ndim > 0 to an index will result in an error in the future',), category : 'DeprecationWarning', filename : '/Users/hendrikheuer/Projects/scikit-learn/sklearn/linear_model/least_angle.py', lineno : 368, line : None})
```

Thank you for this awesome library!

Kind regards and all the best from Stockholm!
Hendrik