* jpgraph seems to be finally dying with PHP. Until we have a valid alternative, disabling this run for PHP because it errors
https://github.com/HuasoFoundries/jpgraph looks like a natural successor, but it isn't BC so it will require some work to integrate
- 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
Column indexes are always based on 1 everywhere in PhpSpreadsheet.
This is consistent with rows starting at 1, as well as Excel
function `COLUMN()`. It should also make it easier to reason about
columns and rows and remove any doubts whether a specific method is
expecting 0 based or 1 based indexes.
Fixes#273
Fixes https://github.com/PHPOffice/PHPExcel/issues/307
Fixes https://github.com/PHPOffice/PHPExcel/issues/476