Cassandre trading bot 3.0.0 released

This is a major release! I think we now have all the required functionality for production. The next major release will have an app and a website to see your positions in real-time.

• Manage several trades for one order situation.

• Improved dry mode (now simulate positions, orders, trades, and accounts).

• Improved documentation on how to deploy your bot with docker.

• Added a getGains on positionsService to retrieve the total gains of all positions.

• Position now stores min and max gain made until the position is closed.

• Added a toString() method on position to display a user-friendly description of the position.

• Added a parameter to automatically add a table prefix to your trading bot backup. This allows you to run several bots on the same server.

Broken: the backup database structure changed so you can’t stop a previous trading bot and restart it with this release.