Revert "changes related to index of genesis block (from privatecoin-2014-01-17)"

This reverts commit 03e4907d40836cf70ee4702d750ae6eb18f10169.
Revert "remove most of the code in InitBlockIndex and change values of hashGenesisBlock, starting difficulty (bnProofOfWorkLimit), and pchMessageStart (from privatecoin-2014-01-17)""

This reverts commit 2d9cf89c4dbd5d0b9d8d790904c53cb6272ee3d6.
- set new genesis block
- added missing genesis block mining code
updated coin parameters, regenerated genesis block
limit difficulty changes to no more than 10% up or 50% down
update checkpoints
Merge branch 'develop'