* Add kernel commitments sum and kernel and output MMR sizes to block header
* Sum a block without including previous sums, cleanup. Blocks are now summed and validated based on their own totals and not the totals since genesis. This allows to get rid of BlockSum and simplified the setting of a new block's roots, kernel sum and MMR sizes. Fixes#116
* Additional kernel MMR validation to check all prior header roots successively
* Wallet tests fix
* large updates for mining, fix async mode, will list changes in PR
* reset config and build defaults
* change to difficulty calculations
* tweaking mining params and tests
* tweaking to tests
* including pre-genesis data for difficulty adjustments, adding adjustment scenario tests
* further clarifying next_difficulty function
* moving tests out of consensus.rs
* pow test fix
* changing pre-genesis generation
