Input keys implementation; binary and source breaking change for the .Seq() configuration method, because the existing strategy for overloading configuration won't work out nicely as new options are added. This will merge as client v2.
Seq "Input keys" renamed to "API keys"
Switch to timer-based, rather than thread-based, implementation for the HTTP log shipper, so that the running thread does not delay process exit.
Merge pull request #7 from continuousit/feature-inputkeys

Support for Seq 1.1 API keys