Merge pull request #3 from journeyapps/master

Detect undefined properties and identifiers, and invalid function calls
Add tests.
Update README.md
Update README.md
Update README.md
Update README.md
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Add failing tests.
Record the scope during the walk.
Do not warn on identifiers when the originNode is known.
Don't warn on unknown properties if the parent type is not known.
Merge pull request #9 from journeyapps/fix-scoping-issues

Fix (some) false negatives
Refactor adding message to prepare custom lint for function call. See
https://github.com/angelozerr/tern.lint/issues/5 and
https://github.com/angelozerr/tern.lint/issues/6
Custom lint for yui+node.js. See
https://github.com/angelozerr/tern.lint/issues/6
Update README.md
Update README.md