further work on churn tests
Merge remote-tracking branch 'maidsafe/routing_v2' into routing_v2

Conflicts:
	src/maidsafe/routing/routing_table.cc
	src/maidsafe/routing/routing_table.h
merging
bugfix for missing public_key
added churn tests - appears a steady 40% of network dropped immediately does not affect close group accuracy.
Reduced churn check to 20% as it is very stable at that level (no spurious fails)
Comments
Merge pull request #54 from dirvine/routing_v2

Routing v2