Initial 2.0

• The most important - now you have to do "import Web3swift" (capitalization!) to follow naming convention
• Put the groundwork for implementing hooks and event loops functionality
• In the next minor release WKWebView with injected "web3" provider will be available by default
• One can add or remove "middleware" that intercepts, modifies and even cancel transaction workflow on stages "before assembly" (before obtaining nonce, gas price, etc), "after assembly" (when nonce and gas price is set for transaction) and "before submission" (right before transaction is either signed locally and is sent as raw, or just send to remote node)
• Usage of "Result" framework was removed due to large amount if name conflicts
• Now functions throw instead of returning "Result" wrapper
• "Web3Options" are no longer used, instead two new classes introduced: "ReadTransaction" and "WriteTransaction", that have a variable "transactionOptions" used to specify gas price, limit, nonce policy, value
• ENS functionality is disabled for now, until the next patch version