Changes:

1. We adopt the convention [start, end) for *all* date ranges.
2. Modified PHE case ingestor to reflect this
3. Modified CovidUK to reflect this
4. Corrected a bug in the use of time in simulation.

Changes:

1. Beta2 introduced to measure the effect of inter-ltla commute
2. Introduced chain thinning to reduce size of posterior output

Changes:

1. Replaced 149 UTLAs with 315 LTLAs mixing matrix;
2. Wrote geometric initialisation for censored event times;
3. Modified data ingester to take PHE Anonymised Line Listing data.

Working event time update.  Not compatible with XLA due to tf.boolean_mask which depends on tf.where.

Got stochastic model fitting with new bounded convergence respecting adaptive proposal.  However, XLA appears now very slow.