Default nonce does not increase for transactions that are in the pool

[ZakGriffith]

When creating a new transaction while other transactions are still in the pool, the default nonce that appears does not increase for those transactions in the pool. An example is when two transactions were created in our test multisig, both got the default of 2. That second proposed transactions should have detected the transaction in the pool was already using nonce 2 and increased the nonce to 3 without the user having to do that manually.