Avoid explicitly using project properties to set task properties in plugin. There are other options for plugin users to provide their own property values:

* Use the override plugin
* Create enhanced tasks of custom tasks brought in by the base plugin
Added test for checking mandatory input properties for StashTask.
Updated documentation.
Avoid call to set up StashTask properties in every test method.
Fix custom task names.
Fix custom task names.
Merge pull request #3 from bmuschko/avoid-explicit-properties

Avoid explicitly setting task properties via project properties