LSTMStateTransitionModel: Normalizing Inputs

**Requirement Text**
Add configurable ability to normalize inputs for LSTMStateTransitionModel.from_data

**Background Information**
Normalizing inputs is important for performance

**Suggested Solution**
Simple normalization - (value-mean) / std - will then have to reverse on the other end

**DoD**
 - [ ] Implement feature
 - [ ] Add tests 
 - [ ] Add to doc comments
