Merge pull request #762 from bvssvni/master

Reexport ai_behavior under piston
Point back to cybergeek94/img_hash

Closes #752
Update dependencies.
FIX: Changed project reference link
Merge pull request #776 from murilocadanus/master

FIX: Changed project reference link
Removed less frequently used libraries

Closes https://github.com/PistonDevelopers/piston/issues/777