* move IResearchViewSort into separate unit
* ensure sort is propagated to IResearchLink
* update iresearch and extend some tests
* implement insertion of sorted values, store value comparator in link
* add tests for VPackComparer
* minor cleanup
* fix issue with sort definiton propagation
* propagate error message from index factory
* add integration tests for sorted indexes, single server
* initial implementation of IResearchViewMergeExecutor
* move iresearch::VPackComparer to separate translation unit
* store collection in IndexReadBuffer for IResearchViewMergeExecutor
* set primary sort from optimizer rule
* add some tests for sorted view case
* extend IResearchViewNode tests
* simplify primary sort definition
* pretty print order condition covered by arangosearch in query explanation
* fix compilation with g++-8
* address catch test failures
* fix tests
* adjust arangosearch optimizer rule to optimize sort in case of cluster
* make tests for sorted indexes work in cluster too
* fix tests
* extend js tests for sorted indices
* fix keyword in query explainer
* ensure sort-limit rule works with views
* backport ngram analyzer fix from upstream
* address jslint errors
* modify IResearchViewSort to support boolean direction specification format
* add some tests
* add tests
* add skip functionality
* extend tests
* add more catch tests
* inline some methods
* address jslint errors
* extend catch tests to reproduce the failure
* add some tests for check fullcount
* add more tests
* extend tests
* temporarily comment out broken tests
* extend js tests
* address review comments
* address jslint errors
* update iresearch
* issue 526.3: update analyzer feature to store analyzer definitions in per-vocbase system collections
* address merge issues
* address another merge issue
* issue 496.1: switch scope of responsibility between a TRI_vocbase_t and a LogicalView in respect to view creation/deletion
* backport: address test failures
* backport: ensure arangosearch links get exported in the dump
* backport: ensure view is created during restore on the coordinator
* Updates for ArangoSearch DDL tests, IResearchView unregistration and known issues
* Add fix for internal issue 483
* add initial implementation of scatter view rule and node
* add tests for `IResearchViewNode` and `IResearchViewScatterNode`
* add missing check
* modify IResearch execution nodes to use references instead of pointers
* use view id in searialized `ExecutionNode` representation instead of the name
* add cluster mode stubs and checks
* very first attempt to distribute IResearchViewNode
* further implementation of cluster-wide arangosearch views
* fix invalid json format
* add tests for coordinator iresearch view
* allow to retrieve a list of existing views on a coordinator
* more tests for coordinator iresearch view
* some fixes to enable query explanation
* remove Collection dependency from RemoteNode
* remove unnecessary remote ArangoSearch view scatter
* fix explanation appearance
* add some assertions
* minor fixes
* implement IResearchViewCoordinator::updateProperties
* fix view DDL issues
* handle link modifications in DDL operations
* add coordinator implementation of iresearch view links
* fix tests
* further coordinator based view DDL implementation
* further IResearchViewCoordinator implementation
* add initial implementation of AgencyMock
* fix some tests
* code cleanup
* extend test + some fixes
* more tests for IResearchViewCoordinator
* fix tests for IResearchLinkCoordinator
* some fixes after merge
* fix tests
* remove declaration of nonexistent (previously removed) method
* some fixes after review
* remove string duplication
* more tests and fixes
* more fixes and tests
* more tests
* one more test
* fix 'use-after-free' asan error
* fix non-enterprise tests issues