Aragon Buidler plugin v0.1.0

Minor changes after the initial release (0.0.7) needed for the plugin to support official Aragon apps like Voting, Finance, Agent, etc.

Changes include:

• Added ability to run on apps that don't have a front end.
• Added ability to interact with a proxy in hooks before it is initialized.
• Normalized hooks interface.
• Bugfix: Update proxies after updating repos.
• Update contract artifacts on smart contract changes.
• Clean up and close all watchers on program exit.