Added Survey From Field validation. Also added the COMMENT_PREFIX in Survey model to ensure that comments are stored in the same way everwhere. Reviewed by: Lennard de Rijk

# use glob syntax.
syntax: glob

*.pyc
*.zip
*~
.project
.pydevproject
app.yaml
build
tests/coverageResults
*,cover
tests/.coverage
*.git
.gitignore
.DS_Store
.settings