Merge branch 'aql2' of https://github.com/triAGENS/ArangoDB into aql2

Conflicts:
	arangod/Aql/ExecutionBlock.h
	arangod/Aql/ExecutionEngine.cpp
removing unnecessary transaction from EnumerateListBlock.
Merge branch 'aql2' of ssh://github.com/triAGENS/ArangoDB into aql2
Implement subquery block - these parameters also should be enabled.
removed a remaining getOne()
EnumerateListBlock now working for JSON lists and prepended "explicit" to Json constructors..
Merge branch 'aql2' of ssh://github.com/triAGENS/ArangoDB into aql2
fixed missing collections
EnumerateListBlock working for ranges.
Merge branch 'aql2' of https://github.com/triAGENS/ArangoDB into aql2

Conflicts:
	arangod/Aql/ExecutionBlock.h
fixed assertion errors
Merge branch 'aql2' of https://github.com/triAGENS/ArangoDB into aql2
refactoring
Fix static analysis for subqueries.
Merge branch 'aql2' of ssh://github.com/triAGENS/ArangoDB into aql2
Add an initialiser.
EnumerateListBlock now works with DOCVECs.
Merge branch 'aql2' of ssh://github.com/triAGENS/ArangoDB into aql2
collect
Merge branch 'aql2' of https://github.com/triAGENS/ArangoDB into aql2