feat(client/deis): add python3 support

Changes:
- use python future for single source
- change octals to new style of `0oXXX`
- add `future==0.14.1` as dependency

Breaking Changes:
- `future==0.14.1` requires python >= 2.6
```
--> python2.7 
Python 2.7.7 (default, Aug  4 2014, 07:49:13) 
[GCC 4.7.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> print 0o700
448
```

Sorry, had never seen that syntax before, assumed it was new.