Documentation for object chaining with keys

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Test for object chaining with keys

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Error raised when key not found

Signed-off-by: Nathan Stier <nathan.stier@gmail.com>
Merge pull request #11 from LonelyRobotStudio/feature-traits

Feature traits