started working on xsede tutorial material

General improvements

* all examples now use the 'new' style API (i.e., no dicts).
* key parameters are moved to the constants in the header
* added error handling an coordinated shutdown in case of error

So far I have:

* Example 01: Simple Ensemble.
* Example 02: Added file transfer. Output files are now copied back!
* Example 03: Task set B now actually use output of tasks from set A ;-)

I will continue working on this during the week