Implementation in TreePPL

The QT model will be part of the official TreePPL release.

However, until then use https://github.com/vsenderov/qtbirds.tppl.

• qt-1.tppl: Inference for Algorithm 1
• qt-2.tppl: Inference for Algorithm 2
• qtbirds.tppl: (deprecated) older version of the inference, where I was experimenting with uniform priors