* Improved handling of named ranges, although there are still some issues (names ranges using a union type with an overlap don't handle the overlap twice, which as the MS Excel approach to set overlaps as opposed to the mathematical approach which only applies overlap values once)
* Fix tests that misused space and comma as simple separators in cell ranges
* Another collection of minor improvements
* Fix broken test
* And style
* Seriously?!? The order of returned types declared in a docblock is majorly important?
When extracting sheet title from string reference (like `"Work!sheet1!A1"`), PHP function `explode()` divide this string into three parts: `['Work', 'sheet1', 'A1']`. And then these wrong values are used in formulas, ranges, etc.
This change fix that problem by using special function `Worksheet::extractSheetTitle()`. This function also has been changed to make sure that worksheet title can contain "!" character. So, that function search last position of "!" in reference string and divide it to 2 parts correctly: `['Work!sheet1', 'A1']`.
Fixes#325Fixes#662
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