Improved prices calculation and remove an error.

This release includes:

• Fixing error with firstTradeTimestamp property on Users and Tokens making a not nullable prop assigning 0 when the value wasn't set.
• Improving prices calculation turning 0xeeeeeee... address into the wrapped native token for calculating prices

First release v0.1.0

This release includes changes documented here

Latest changes include:

• including token entity relations to token totals.
• added pair entity prices.
• splited tokens traded in cow form uniswapTokens to be different entites to improve queries performance.
• calculated relative prices.
• updated some names to keep convention.