Addition Transaction Verification Rules

[lancekrogers]

1. Adding additional transaction verification rules
   1. For all asset transactions follow these additional steps
   2. Check the weight of the asset. If the weight is not 0:
      1. If the weight is 1 check for a consortium signature:
         1. if signatures are not present the transaction is not valid
      2. If the weight is 2 check for both consortium and municipal signatures
         1. if signatures are not present the transaction is not valid
      3. Delete expired transactions from node