better error handling
support case that no Server header was delivered
better result reporting
fix: don't CloseAll...
Which IDE version was used.
Accessed URIs modified.
Merge branch 'better-error-messages' of github.com:jrudolph/sprayreactivedemo

Conflicts solved:
	src/main/scala/crawl/FutureCrawlMain.scala

Worked out and polished so that some resting scaling problems are easily recognizable.
StatisticsActor introduced, sorts entries.