Update badge style for consistency

[ci skip]
add toshi link to docs
Merge pull request #83 from rrrene/patch-2

Update badge style for consistency
Fix concurrency issue; fix 0conf balance
Merge pull request #79 from aalness/andy_fix_concurrency

Fix concurrency issue; fix 0conf balance
Merge pull request #84 from rnicoll/master-dogecoin-genesis

Add Dogecoin genesis block configurations
Add preliminary support for Dogecoin.

Added Dogecoin network protocol version numbers and pre-Digibyte support for Dogecoin difficulty calculations.
Initial draft of calculations post-Digibyte are in place, but untested and commented out. Placeholder
inserted for AuxPoW handling.
Add Dogecoin difficulty hardforks

This adds the code to handle Digishield difficulty calculations for Dogecoin,
as well as correctly setting the switch-over block for when Dogecoin's testnet
difficulty calculations change to enable resets.
Corrected target time for Dogecoin post the Digishield switchover block.