Merge pull request #335 from nblumhardt/dev

First checklist item from #125 - remove `dynamic`
Changed to use stream for HTTP in Splunk
Merge pull request #336 from merbla/splunkstream

Changed to use stream for HTTP in Splunk (#215)
Add pre-built binaries for ASP.NET 5

VS2015 is in preview and not really suitable as a CI dependency; but, a lot of people are interested in using Serlog on ASP.NET 5.0 core (this was contributed by the ASP.NET team). Checking in the binaries lets the production NUPKG support these people while we wait for a closer-to-final VS release we can use in CI.