Schemavalidation Fix Gramex Issue #191

@s.anand Please run npm install -g ajv ajv-cli in the gitlab CI environment.

Post that the script should run -

Had to wrap yamllint in builderrorutils.py in a try catch block as very badly formatted gramex.yaml files were causing it to crash.

Also flake8 did not like me writing the yaml file to a utf-8 dictionary, so disabled the check for the unicode() function - this can be undone once the runner is on python 3.