v1.1.1: Fix allow min difficulty blocks #13

• fixed bug in allowMinDifficultyBlocks section
• updated readme

v1.1.0: Fix and adapt for mainnet and testnet (#11)

Fixed and adapted for mainnet and testnet

• fix jsdoc

• adding network param

• updating tests

• add mainnet blocks and test

• correct mainnet test target

• replace isValidTarget with hasValidTarget

• fix getNetworkParams

• replace 150 with param powTargetSpacing

• remove throw error

• revert to u256 primitive

• rem getDoubleFrom256 usage

• rem brackets

• improve comments

• reduce reduce function

• rem getTarget from export

• add test headers and fix tests

• bump version

• rem utils

• ignore .idea

• update package lock

• rem unnecessary bn.js from deps

• update package lock