Logging: Add cli option support for log level.
Merge pull request #135 from AlJaMa/master

Changed the Client's setField function to take a datagram iter
Merge pull request #136 from Astron/LogLevel

Logging: Renames spam to trace, Bugfix: Fixes FindYamlCpp on Windows
ClientAgent: Change-location messages should also be given a historical-object grace period.
ClientAgent: Check for client version mismatch BEFORE DC hash mismatch. This allows the more descriptive error to be shown in the event both are invalid.
ClientAgent: Add object IDs to the history when deleted.
ClientAgent: Fix CLIENT_HELLO read order, which I messed up in 97b56ee.
Merge pull request #137 from Astron/clientagent-fixes

Various Client Agent fixes