Fixed some malformed Javadoc
Moved rendering examples into examples module

These had been in a temporary package called 'dave'. They've now
been moved into qtiworks-code-examples and slightly tidied up.
Added "Candidate Activity Log" to proctoring

This shows a simple list of all candidate events logged, formatting
in a reasonable fashion. Very simple for now, but useful for the
diagnostic testing pilot being performed at the moment.
Added new SimpleJqtiFacade, tidied examples

SimpleJqtiFacade is intended to be a very simple facade API for the
main read, write and run functionality in JQTI+. This should cater for
very basic use cases, and also help people see how to join the lower
level bits up more clearly.

Still needs a bit more work...

I have updated the existing examples to use this where appropriate.
Tidied up exceptions in candidate service API

Renamed CandidateForbiddenException as CandidateException
and CandidatePrivilege as CandidateExceptionReason.

Also update the names of the various reasons to make them
clearer, and added in some Javadoc.
Partial refactoring of Privilege/Exception

Moved anything specific to candidates to CandidateException
for better consistency.
Tidy of exceptions in main service layer

* AssessmentStateException is now AssessmentManagementException
* AssessmentPackageFileImportException -> AssessmentPackageDataImportException
* Renamed the inner enums in both of the above
Further exception refactoring...

I decided to replace AMException with concrete exceptions for the 2
cases it ended up covering. This makes it easier to understand when and
how such exceptions happen and propagate.
RequestTimestampContext minor fix

This now removes the underlying ThreadLocal value when setting to null.
Moved some classes in qtiworks.domain package

I've moved some classes that had been languishing in the top domain
package closer into more appropriate places.
Minor enhancement to exploded/terminate rendering

The rendered HTML for these 2 cases now includes the session exit URL
(if available).
Fixed a couple of minor regressions in author view