Stock charts currently ignore upDownBars tag and its subsidiary gapWidth, upBars, and downBars tags when reading, and hard-codes those tags on write. As a result, the sample reproductions of stock charts in the 32* series aren't faithful to the originals. This PR fixes samples 1, 2, and 5. Samples 3 and 4 are reproduced better, but they require currently unsupported secondary axes (issue #560, issue #1072, and PR #1073 were closed as stale; see also https://github.com/PHPOffice/PHPExcel/pull/1037). I will start to look at those, but it could take a while, and I don't think there's a reason to delay this in the meantime.
Charts which depended on the hard-coded values written by the Xlsx Chart writer will be slightly different as a result of this change. To restore the hard-coded behavior:
```php
$plotArea->setGapWidth(300);
$plotArea->setUseUpBars(true);
$plotArea->setUseDownBars(true);
```
The new behavior is demonstrated in 33_Chart_create_stock. The old behavior is demonstrated (with the code above) in new 33_Chart_create_stock2.
This introduce a helper class that should be used to log things,
avoiding a lot of boilerplate code.
Also all output are made in /tmp folder instead of beside the script
itself. This is because there is a high chance that the folder containing
the script is not writtable by webserver. So using the /tmp folder
makes it more likely to works in a variety of setup.
oleibman
Adrien Crivelli