Adding 'get' command to the CLI, to view a single variable.

This enables the user to type "get variablename" in the CLI, which then shows the value of that variable (or a message saying "Variable 'variablename' not found").
This is easier for the user when they just want to see a single variable, instead of typing 'dump' and then having to parse a big long list of data.  It is also more intuitive than typing 'set variablename', as this feels unsafe.