* Made usage of named variables for targets a little more consistent
* Bumped minimum cmake version
- removed policies superseded by minimum cmake version
- fixed static linking due to new policy CMP0060
* Fixed library suffixes for windows
* Extracted libs arango_mmfiles and _rocksdb from arangoserver
* Replaced target variables by constants
* Extracted arango_cluster_engine from arangoserver
* Extracted llhttp from arangoserver
* First successful split of arangoserver
* Moved enterprise files to enterprise
* Again only optionally include RestTestHandler and AcceptorUnixDomain
* Cleaned source files from other libraries
* Removed old commented sources
* Split off a small third library
* Fixed boost dependency for cluster engine
* Added some missing dependencies
* Added arango_geo dep, and -J on windows
* Began to split off an arango_graph lib
* Moved more files to arango_graph
* Do not set /J globally for ATL
* Moved more files to arango_graph
* Moved graph-RestHandlers to arango_graph
* Added arango_geo dependency to _mmfiles and _rocksdb
* Updated graph dependencies
* Split off arango_pregel
* Split off arango_aql
* Added missing boost_system dependency to pregel
* Split off arango_vocbase
* Cleanup
* Added missing boost_system dependency for arango_vocbase
* Split off arango_v8server
* Split off arango_utils
* Minor cleanup
* Split of arango_storage_engine
* Split off arango_indexes and arango_cache
* Fixed some dependencies
* Split off arango_replication
* Resolved two todos
* Split off arango_agency
* Reordered some statements
* Ordered dependency definitions alphabetically
* Cleaned some deps
* Break one cycle, comment on another
* Merge the remaining arangoserver_part[123] sources
* Moved some utils to vocbase to break cycles
* Added missing backtrace dependency to iresearch-s
* Added missing boost dependency
* Added dependency arango_indexes -> arango_geo
* Added deps to arango_cluster_engine, cleaned duplicate deps
* Broke remaining dependency cycles
* Actually, missed one cycle...
* Re-added include for Mac
* arango_cache needs SharedPRNG
* allow to access last operation tick of the transaction
* modify IResearchLink to rely on last commtted tick
* get rid of writing arangosearch markers to WAL
* further implementation
* local changes in iresearch
* add recovery states
* properly handle link creation during recovery
* adjust test cases
* properly handle nested transactions
* ungreylist recovery tests
* add more recovery tests
* do not use transaction to pass recovery tick
* do not store recoveryTick in MMFilesRecoveryState
* adjust tests
* fix mmfiles
* cleanup
* add context validity check
* fix tests
* fix more tests
* ensure subscription is not being released during commit
* address review comment
* final cleanup
* fix crash
* fix tests
* address test failures
* address review comments
* address review comments
* properly set recovery tick even if no recovery happened
* issue 381.4.1: create a separate IResearchLink implementation for use with ClusterEngine
* backport: ensure StorageEngineMock assigns unique transaction ids
* delegate index normalization on the ClusterEngine to the 'actualEngine'