Migrated to Guava 0.14.1

(Removed use of deprecated Closeables in the process)
Updated to Spring 3.2.2
Ran findbugs and fixed some minor issues in jqti+
Ran findbugs on qtiworks-engine
Updated maven compiler to 3.1

(3.0 was a bit buggy!)
Removed stuff accidentally added to choice.xml
Change to ZIP/XML import logic

Fixes bug #28. We no longer check the MIME type of ZIP content
and instead try to expand it and succeed if a valid ZIP entry is
found. Some changes have been made to the API to accommodate this
safely.
Fixed inappropriate use of RedirectAttributes
Refactored IoUtilities down to nothing

* Some methods moved to ServiceUtilities, and now throw
QtiworksRuntimeException if things go wrong
* Other methods replaced with analogues in Apache commons-io
Merge branch 'master' into rendering_refactoring

Conflicts:
	qtiworks-engine/src/main/java/uk/ac/ed/ph/qtiworks/services/AssessmentPackageFileImporter.java
	qtiworks-engine/src/main/java/uk/ac/ed/ph/qtiworks/services/StandaloneValidationService.java
	qtiworks-engine/src/test/java/uk/ac/ed/ph/qtiworks/services/AssessmentPackageFileImporterTest.java
Improved link for invoking author view
Changed the toggling for validation results
Validation JSPs now flag warnings differently
Added validation results to candidate session
Engine bootstrap now adds default delivery setngs