* Breaking Change to toFormattedString and 3 toArray Methods
DocBlock says `toFormattedString` returns string, but code can return int, float, bool, null, or RichText. I think the DocBlock is correct (function name clearly indicates "to string"), and the code needs to change to match it. This is not that big a deal on its own. However, some methods in `Worksheet` call this function by default - `rangeToArray`, `toArray`, and `namedRangeToArray`. All 3 can be called with a parameter so that they don't call `toFormattedString`, but, by default, they do call, and so are affected by this change. Some unit test results are changed as a result of this code change. In all those cases, an additional test is added which would match the previous result.
* Update Change Log
I often skip this till later, but, since it's a breaking change ...
* Scrutinizer, Plus Strange Cast to -0
Avoid Scrutinizer complaint by casting string to float, but ... Php decides resulted should sometimes be `-0`? That caused test failures. Very odd.
Fix#2488. When Excel sees this situation, it leaves the value of the cell as null rather than casting to the specified DataType. It doesn't really make sense to change setValueExplicit to adopt this convention; it should be sufficient to recognize the situation in the Reader and act there. The same sort of situation might apply to strings, but I don't see any practical difference between null string and null even if so.