Fix for comments that contain unicode

For example, a comment like `com – ment` bonks on `$ git story -c` with the following traceback:

```
Traceback (most recent call last):
  File "<string>", line 16, in <module>
  File "/private/tmp/continuity-1DRzO2/continuity-0.9.6/build/continuity/out00-PYZ.pyz/continuity.cli", line 134, in main
  File "/private/tmp/continuity-1DRzO2/continuity-0.9.6/build/continuity/out00-PYZ.pyz/continuity.cli.commons", line 84, in __call__
  File "/private/tmp/continuity-1DRzO2/continuity-0.9.6/build/continuity/out00-PYZ.pyz/continuity.cli.pt", line 374, in execute
  File "build/bdist.macosx-10.9-intel/egg/clint/textui/core.py", line 58, in puts
UnicodeEncodeError: 'ascii' codec can't encode character u'\u2013' in position 4: ordinal not in range(128)
```