Wallet Addresses return in lower case and it is causing issues for devs

[JAlbertCode]

When a dev tries to validate a wallet address they are running into issues because the web3.Signer.GetAddress() function returns an address in all lower case. So when they check if the wallets match, it returns false even though the addresses are the same. The following script resolves the issue and needs to be added to the docs.

// Put this at the top of your script, it's a using directive to give you access to the helper method.
using Nethereum.Util;

// This is your checksum function, place it anywhere.

/// <summary>
/// Converts an address to checksum format.
/// </summary>
private string ConvertToChecksum(string address)
{
    string checksumAddress = new AddressUtil().ConvertToChecksumAddress(address);
    return checksumAddress;
}

// Call it like this.
var checksumAddress = ConvertToChecksum(Your Address Here);

[sneakzttv]

added to #156