1. More fixes to improve download speed of the block snapshot files.
2. Reinstated the skip analysis optimisation for Ethereum mainnet, introduced skip analysis optimisation for BSC mainnet (only up to block 11m for now).
3. Further simplifications to header downloader
4. Fixed the issue of stuck header downloader right after the snapshots.
5. Ropsten block snapshots are added and activated by default.
6. Ropsten TTD (Terminal Total Difficulty) added to the configuration.