New Checkpointing Policy

Checkpoint by block height rather than block time;
-checkpointdepth start-up switch implemented for depth control.
Hard Fork and Many Other Improvements

- a hard fork to reduce interval of stake modifiers from 6 to 3 hours;
- the block limiter improved to prevent abusive future travels;
- serialisation support added for pruned transactions;
- better detection and management of failed transactions;
- Qt GUI minor fixes and enhancements;
- various clean-ups and optimisations.
Some Minor Corrections
Some Minor Corrections (cont'd)
Stake Mining Settings Optimised

- stake split threshold introduced;
- small inputs combined and average inputs are never split;
- bug fix: combine threshold must be reached, not necessarily exceeded.

These optimisations also decrease average stake transaction size.