Fix CI and GeoLite2

[andronat]

Various fixes to make CI pass. More details:

• Updated dependencies for security updates
• Fixed CI issues with python3
• Download and use the offline version of GeoLite2
• Updated Circle CI image
• Freeze Klee version

Fixes #156

[ccadar]

@andronat Thanks for all the excellent changes!! I'll update the CircleCI changes and merge this.