servable dependency uses Python 2 syntax, causing import errors

[bmander]

Problem

The servable package dependency uses Python 2 syntax which causes syntax errors when importing the graphcrawler module:

File "/workspaces/graphserver/pygs/graphserver/ext/graphcrawler.py", line 4, in <module>
  from servable import Servable
File "/usr/local/python/3.12.1/lib/python3.12/site-packages/servable.py", line 134
  print "starting HTTP server"
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
SyntaxError: Missing parentheses in call to 'print'. Did you mean print(...)?

Impact

This prevents the CLI from loading and blocks testing of the migrated click-based commands.

Potential Solutions

1. Find a Python 3 compatible version of servable
2. Replace servable with a modern alternative (like Flask)
3. Make the graphcrawler import optional with proper error handling
4. Vendor/fork servable and fix the Python 3 compatibility issues

Workaround

For now, we could make the graphcrawler import optional to allow testing other CLI commands.