Hard fork release

Reject spam transaction.
Add Checkpoints.
Hard fork with Block height 316000.
Change mining reward of 1 block to 10 after hard fork.

mangacoin-0.15.2.6 :Fix crash bug with duplicate inputs within a transaction and more

• bootstrap(2018/11/27) 5.81GB
  https://www.dropbox.com/s/7oiuz7fc97by7as/bootstrap.zip?dl=0

mangacoin-0.15.2.5: add checkpoint

increment build version number

ビルド番号を＋１

mangacoin-0.15.2.4: First release

Replaced background image