Update log

1. Fixed the problem when k=33 in the plot file in mass calculation.
2. When the height is 200040, the Plot filter is turned on, and the number of digits is 5.
3. Add some optimizations for reading plot files.
4. The RPC command querynetspace now returns the value of current estimated netspace.

Because the consensus mechanism has been modified, it is necessary to return to the height of 200,000 for testing.