Fix reorg handling
Merge pull request #85 from aalness/andy_reorg_fix

Fix reorg handling
Fix MemoryPool#remove to not use recursion
Oops
Merge pull request #97 from aalness/andy_fix_rm_conflicts

Fix MemoryPool#remove to not use recursion
Fix off-by-1 error
Merge pull request #100 from aalness/fix_confs

Fix off-by-1 error
Add Dogecoin support

Added Dogecoin network protocol version numbers.
Added Digishield difficulty calculations for Dogecoin.
Dogecoin testnet difficulty reset now functions correctly.
Added initial draft of AuxPoW handling, primarily for Dogecoin at this time however
any chain following the Namecoin merged mining specification should work. AuxPoW blocks
are now identified, and the AuxPoW data validated and checked against the difficulty of
that block.
Cleaned up code based on feedback.
Updated minimum work that can be required for a block to handle Dogecoin Digishield blocks.
Moved difficulty target calculation code into Bitcoin-Ruby.