Impl: Clickable and Colored MenuItems

Implementation for #2.

menu items can be made clickable by providing a `href=..` parameter and the text color can be changed with the `color=..`parameter.
```bash
echo "foo menu | color=purple"
echo "---"
echo "ticket XYZ | href=http://somewhere.com/ticket/XYZ"
echo "hex colors work too | color=#123edf"
```