Add link to additional python implementation

[djmattyg007]

I created this implementation by forking the now-defunct original kdl-py implementation. It differs from the existing implementation in a few important ways:

• It provides a more python-native interface akin to the existing JSON and YAML packages
• It provides powerful support for custom types, while ensuring support for built-in types is first-class
• It deliberately doesn't provide as much control over the encoding process as kdl-py does

[zkat]

Note that the currently listed Python implementation is by @tabatkins and it's actually pretty well maintained, but I don't see anything wrong with having multiple implementations myself.

[djmattyg007]

I started working on cuddle almost a month ago, shortly after the announcement of KDL 1.0 being formalised. At the time, the only implementation I was aware of was the broken version of kdl-py.

[tabatkins]

Nice, my kdl-py was an entirely fresh impl just after the 1.0 announcement, because I saw the existing py impl was defunct 😀