Issue 414: list constraints

[jeswr]

Closes #414. This PR implements sh:minListLength, sh:maxListLength and sh:uniqList.

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My interpretation of the following from the definition of 2.1.1 Constraints, Parameters and Constraint Components is that because the sh:MemberShapeConstraintComponent now has multiple parameters; there can only be one occurrence of sh:memberShape in a given shape - and I have updated the sh:maxCount accordingly.

Some constraint components declare only a single parameter. For example sh:ClassConstraintComponent has the single parameter sh:class. These parameters may be used multiple times in the same shape, and each value of such a parameter declares an individual constraint. The interpretation of such declarations is conjunction, i.e. all constraints apply. The following example specifies that the values of ex:customer have to be SHACL instances of both ex:Customer and ex:Person.

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This is currently targeted to #403 branch for a smaller diff in the GH UI. #403 should be merged and this targeted to gh-pages rather than merging this branch into #403

[HolgerKnublauch]

I am in the middle of implementing all this in Java and found various issues.

[jeswr]

I have addressed the issues found - is there an(other?) open source implementation that'd be useful for me to implement the changes against (@bergos' JS shacl-engine perhaps) in case there are any more errors to catch.

P.S. I am conferencing for the next 3 days so will be slow to respond

[jeswr]

Thanks for the fixes @HolgerKnublauch

In case needed as future provenance for others: note that 58daff6 makes it such that if a list is malformed - the sh:value should always be the head of the list - not the first malformed node.