Upgrading exam features
- Slightly changed the format returned for certain questions in order to
enable better postprocessing and reviewing of answers.
- Changed the Course model accordingly.
Adapted prelude files in generated HTML for exams
Adapted Tutor to dropbox
- Adapted path names
- Generate .html  and lock.htaccess in exams directory
- Generate .quest in results directory
Improved handling of exam results.
Adding custom annotation @breakable for future debugging implementation.

Usage:
* @breakable at the beginning of an production, refers to the whole production.
* @breakable{name} refers to the application of a non-terminal with name 'name' within the production.
Updating copyright notice and contributions.
Regenerating AST files from grammar, due to previous change.
Updating copyright notice and contributions.
Fixed handling of Num types in type reifier
- a num erroneously returned a node type
Now correctly recreate the URI
Replaced all getHost/Port with getAuthority
Demo for debugging with context sensitive annotations.
Fixed the new URI("") and URI.create calls
fixed a large memory leak in the Rascal module parser. The set of
productions in the module environment would grow incrementally with
every edit action.
Added a restriction of the priority filter to fix bug in implementation
pointed out by Liz Scott.
* action executors can now also get the entire tree as a first argument.
* made sure action executors get annotated trees, such that
disambiguation information can use layout information
(pair programmed with Sebastian)
added documentation about when a priority filter works, depending on the
recursive positions of the parent and child productions
* improved doc of assoc and prio
-Fixed the end location of the skipping stack node.
Merge pull request #10 from Da-Huntha/master

Content Completion MissGrant standard library example.