v0.2.0-rc7

Changes:

• Added Proxy Calls, Events and examples.
• Added examples for account creation
• Added function that generates random substrate account
• Added Session Calls
• Added example for setting up a Validator
• Added Tip and Mortality (Validity) to Transaction Options
• Added Tip(), Mortality(), and Nonce() methods to BlockTransaction
• Changed how IsSuccessful works. It now returns an Optional : Returns None if there was no way to determine the success status of a transaction. Otherwise it returns true or false.
• All the Block Transaction examples showcase how to get Tx Signer, App Id, Tip, Mortality and Nonce from block transaction.