custom prop removeTargetFolder

[MartinKl]

Create a customization property for entire Pepper, to remove an export folder before the job starts. So for instance if the export folder is A and A already exists on disk and contains data, they will be removed, before the export starts. Therefore a customization property for entire Pepper, not just a module, see:

<pepper-job id="" version="1.0">
<customization>
<property key="removeTargetFolder">true</property>
</customization>
...