added no-warning-comments rule

squashed commits:
* added no-warning-comments rule
* extended documentation with some examples
* warningTerms are no longer passed as they are already in the context
* rule is now configured with an additional configuration object
* extended and rearranged documentation for no-warning-comments rule
* added JSDoc comments
Merge pull request #671 from lusini/add-no-warning-comments

Added no-warning-comments rule (fixes #660)