s4cmd not able to load utils.py for cmp_to_key on python 2.6

When installing s4cmd on a CentOS 6.5 system with Python 2.6 (required for another application) using pip, the utils.py file is not installed, resulting in an error when running s4cmd because it can't import the cmp_to_key function. If I manually drop a copy of utils.py in /usr/bin (where s4cmd is also placed), s4cmd runs correctly without error.

```
Traceback (most recent call last):
File "/usr/bin/s4cmd", line 7, in
from s4cmd import main
File "/usr/bin/s4cmd.py", line 43, in
from utils import cmp_to_key
ImportError: No module named utils
```

Reproduce the pip installation on Python 2.6 and inspect the installed s4cmd files, especially whether utils.py is included alongside s4cmd.py. Run s4cmd to confirm the ImportError, then verify that a clean installation can import cmp_to_key without manually copying utils.py.

Written by the indexing model from the issue text.