Handle subscription transfer special cases + tests

[mregen]

• Fixed issue: After transfer, available sequence numbers were not properly ack/republished.
• Fixed issue: After transfer, race condition could delete subscription before transfer finished.
• Fixed issue: After reload of a subscription, duplicate client handles may have been used.
• Add tests which emulate the disconnection of a client/server, then transfers
• Add subscription variable to select if missing publish requests are just acknoledged (default) or republished after transfer completes. Set Subscription.RepublishAfterTransfer to true.
• Improve test framework to allow for testing against external servers using a .runsettings file
• improve publish request logging, by moving calls into CoreClientUtils.EventLog
• disable available sequence numbers check, it causes false negatives when many subscriptions are active