Client was logging stack trace in reverse

According to the Sentry docs, stack traces should be logged with the most recent frame [last](http://sentry.readthedocs.org/en/latest/developer/interfaces/index.html).

The .Net StackTrace class used by the library puts the most recent frame [first](http://msdn.microsoft.com/en-au/library/system.diagnostics.stacktrace.getframes.aspx) and hence the client was logging stack frames in reverse. 

I've reversed the stack trace, and dropped in a bit of linq because I think it reads a bit more nicely.