Merge pull request #11 from percyliang/master

Revamped configuration system / generalize cl run
OAuth authentication
Update content of default config file.
Friendlier error message to end-user
Merge pull request #12 from cpoulain/master

OAuth authentication
Fix error message
Merge pull request #14 from cpoulain/master

Fix error message
Fix mixing self argument in method.
Fix undefined variable error (bundle_spec -> spec).
Merge branch 'master' of https://github.com/codalab/codalab-cli
Merge pull request #15 from cpoulain/master

Fix errors reported by PyLint
Merge branch 'master' of github.com:percyliang/codalab-cli