* make the different values influencing the compaction run configurable
* Compaction statistics handling
- we mustn't keep the number of dead objects on the compacted datafiles statistics, else it will be compacted again.
- keep statistics of the compaction runs on the DatafileStatistics object
- add the new statistics on DatafileStatistics to the figures api
- implement test that assures only one compaction is run, and the statistic values are maintained
* don't mention the version number
* Implement review
- fix documentation
- allow 0 maxfiles to enable users to disable combined of datafiles
- add statistic element that counts the number of combined datafiles
* Implement review
- fix documentation
- use locks to make statistic values consistent.
- fix typo in variable name
* fix temporary variable unnecessary.
* changelog
* do not use V8 variant of AQL functions in early optimization stage when a C++ variant is available
* additionally, simplify AQL function definitions and aliases
* warn when more than 90% of max mappings are in use
* added C++ variant of replication catchup
* added `--log.role` option
* updated CHANGELOG
* removed non-existing scheduler.threads option from config
* removed useless __FILE__, __LINE__ invocations
* updated CHANGELOG
* allow a priority V8 context
* remove TRI_CORE_MEM_ZONE
* try to fix Windows errors & warnings
* cleanup
* removed memory zones altogether
* exclude system collections from collection tests
* added V8 context lifetime control options `--javascript.v8-contexts-max-invocations` and `--javascript.v8-contexts-max-age`
* make thread scheduling take into account most of the tasks dispatched via the io service
* ignore some return codes when closing zip files and do not report them
* hide mostly useless debug message
* clear basic authentication cache after deletion of users and after updating them
otherwise deleted/changed users can still access the database!
* adjust wording
* added notes about mmfiles-specific parameters
* updated CHANGELOG and documentation