Merge remote-tracking branch 'origin/2.3' into devel

Conflicts:
	CHANGELOG
added generated files
Merge branch 'devel' of github.com:triAGENS/ArangoDB into devel
Merge branch 'devel' of github.com:triAGENS/ArangoDB into devel
fixed SimpleHttpClient
Reengineer cost estimation completely.

One test failing in single-server-AQL.
Cluster not yet tested.
Merge branch 'devel' of ssh://github.com/triAGENS/ArangoDB into devel
Adjust local test (do not test whether cost estimate is zero).
Fix another test for AQL and new estimates.
removed while loop
Merge branch 'devel' of github.com:triAGENS/ArangoDB into devel
fixed chunked again
Remove a test for cost estimation.
fixed server gone reconnet
Merge branch 'devel' of ssh://github.com/triAGENS/ArangoDB into devel
Fix SimpleHttpClient for the n+1 time. Some major cleanup done.

Added a lot of comments to explain why it should work now properly.
Fix tests with new estimateCost functions.
Merge branch 'devel' of github.com:triAGENS/ArangoDB into 2.3

Conflicts:
	CHANGELOG
	Makefile.in
	configure