Remove NOOPs from OTServerConnection.cpp

Remnants from the SSL mode
Merge pull request #393 from OttoAllmendinger/pr-transport-fixes

Remove NOOPs from OTServerConnection.cpp
Choose minimal available number for transactions

It is only cosmetic fix. Get new numbers for transaction in increasing order.
Merge pull request #390 from mhamrle/nums

Choose minimal available number for transactions
OTCheque: rename class to Cheque
OTCheque: rename files to Cheque.{h,c}pp