AssetResponse does not include liquidity_pools_amount

[GuyWhoKnowsTheGuy]

Describe the bug AssetResponse does not include liquidity_pools_amount

To Reproduce Steps to reproduce the behavior:

1. var assetInfo = await Server.Assets.AssetIssuer( [ any existing account ID ] ).Execute();
2. assetInfo.LiquidityPoolsAmount does not exist. LiquidityPoolsAmount would map to _embedded.records.liquidity_pools_amount.

Expected behavior AssetResponse.LiquidityPoolsAmount would exist and map to _embedded.records.liquidity_pools_amount.

[Kirbyrawr]

Check this to have a reference, it seems i missed adding it https://github.com/stellar/java-stellar-sdk/blob/master/src/main/java/org/stellar/sdk/responses/AssetResponse.java

[GuyWhoKnowsTheGuy]

Fixed in #348.