- Refactoring of the Statistical Conditional functions (`AVERAGEIF()`, `AVERAGEIFS()`, `COUNTIF()`, `COUNTIFS()`, `MAXIFS()` and `MINIFS()` to use the new Database functions codebase.
- Extended unit testing
- Fix handling for null values
- Fixes to wildcard text searches
There's still scope for further improvements to memory usage and performance; but for now the code is stable with all unit tests passing
* Merge branch 'master' of C:\Projects\PHPOffice\PHPSpreadsheet\develop with conflicts.
* More statistical tests
* Further statistical tests
* Unit tests for some of the trend functions
* resolve scrutiniser objections
* Fix order of @return types :-(
* Merge branch 'master' of C:\Projects\PHPOffice\PHPSpreadsheet\develop with conflicts.
* Additional unit tests for average functions, and fix to AVERAGEIF() function if third argument is passed
* Update change log
* Stricter typed comparisons in AVERAGEIF() conditions
* Unit tests for BETADIST() and BETAINV()