CME Enhanced Resend (issue #841)

[gbirchmeier]

Let's consider this one a draft still. Some parts are subject to change.

Please see README-EnhancedResend.md for information

I need to improve the documentation yet, and the "CmeMode" config setting will probably get a better name.

I used the code in this branch to pass 13 CME AutoCert+ scenarios:

1. Dropcopy CGW Session Management Tests - Logon Message
2. Drop Copy CGW - Mid-Week Key Rotation
3. Dropcopy CGW Sequencing Test - Receive Message Stream (No Resend)
4. Dropcopy CGW/MSGW Session Management Test - Beginning of week Logon
5. Dropcopy CGW/MSGW Session Management Test - Mid week Logon process
6. Dropcopy CGW/MSGW Sequencing Tests - Received encapsulated message from simulated Order Mass Action Messages
7. Dropcopy CGW/MSGW Sequencing Tests - Respond to Resend Request
8. Dropcopy CGW/MSGW Sequencing Tests - Bi-Directional Resend Request Scenario
9. Dropcopy CGW/MSGW Sequencing Tests - Process real-time messages during a Resend Response from CME Globex
10. Dropcopy CGW/MSGW Session Management Test - Logon Process with Failover
11. Dropcopy MSGW Session Management Tests - Logon Message
12. Drop Copy MSGW - Mid-Week Key Rotation
13. Dropcopy MSGW Sequencing Test - Receive Message Stream (No Resend)