Added #jumpedByBranchRule to AbsPartSessState

This will be set whenever we jump over a node when evaluating
a branchRule. This will help rendering a lot.

Some refactoring to TestPlan was made to accommodate this,
in particular the combined Map of TestPlanNodes is now just a flat
List.
Added support for EXIT_TEST anywhere.
testPart feedback now ignores jumped items/sectns

This uses the newly added functionality for recording what
nodes when skipped when evaluating a branchRule, as well as
existing similar functionality for preConditions.
Further change to EXIT_TEST handling...

I think it is sensible for this to behave in the same
manner as EXIT_TESTPART when the test only has 1 testPart, as that
would give the caller access to the feedback for the current testPart.
In the case of multiple testParts, we will still end the test itself.
Further minor fix to mathEntry help
Merge branch 'test_implementation' into rendering_refactoring
WIP: Contd new author/debugging XSLT
WIP: Item author view now integrated into MVC
Cotinued item author view:

* Added "view item state" to rendering
* Removed separate allowSource/allowResult from DeliverySettings
Started styling new author view
Further tweaks to item author debug XSLT
Continued item authoring view
Rationalised CSS/JS after recent changes
Fixed typo in MAD01-SRinCO-demo.xml
Removed broken MathML space munging in XSLT.

I don't think this is a problem now that we're using
MathJax, but can come up with a replacement if there does
seem to be an issue.
Minor tidy to rendering examples & docs
Continued with item/test debug rendering...

* Added test debugging
* Refactored XSLT to accommodate this better
* Some more general refactoring on the way
Now supports launching invalid assessments

(As a result, the validation process once again issues
warnings for identifiers that are longer than 32 characters)
Tidied up item/test author debug display
Further improvement to author debug info