* update iresearch to codebase as of 20181011
* backport: address cluster test failures
* backport: address dump test failures
* backport: address discrepency in view creation between single-server and cluster
* backport: address test failure on cluster (revert change)
* backport: address test failures
* backport: address MSVC build issues
* backport: address issue with LogicalDatasource destructing after TRI_vocbase_t
* Revert "backport: address issue with LogicalDatasource destructing after TRI_vocbase_t"
This reverts commit 4f9880bbaa22194dfbb604b5a54658de1d447ac1.
* get rid of memory stores
* do not use 'waitForSync' transaction option to synchronize a view
* honor `Methods::isSingleOperationTransaction()` hint
* explicitly specify index_writer's properties
* ensure data is synced
* fix tests
* another fix
* code cleanup
* remove code duplication
* some fixes
* fix typo