Add support for worksheet directives
Merge pull request #21 from javierluraschi/WorksheetDirectives

Add support for worksheet directives
Validate file system access by bundle
Resolve merge conflict
Remove unwanted file.
Merge branch 'ValidatePaths' of https://github.com/javierluraschi/codalab-cli into review
Validate access to bundle files
fixed issue #25
Merge branch 'master' of https://github.com/codalab/codalab-cli into perms

Conflicts:
	codalab/client/local_bundle_client.py
	codalab/lib/spec_util.py
	codalab/lib/worksheet_util.py
	codalab/server/file_server.py