ST6RI-722 Model library updates from KerML FTF Ballot #3

[seidewitz]

This PR implements resolutions of issues from KerML FTF Ballot 3 that called for updates to library models.

Resolutions of the following issues are implemented in this PR:

• KERML-38 Binary association ends always unique
• KERML-42 Occurrences can be data values
• KERML-43 Performances can be objects, behaviors can be structures *
• KERML-56 Universal features can have many values
• KERML-77 Problems with IfThenElsePerformance
• KERML-88 BaseFunctions::',' has a bad parameter declaration
• KERML-188 DataFunctions::Min and Max should not be capitalized
• KERML-198 Wrong documentation format for class Occurrence in Semantic Library
• KERML-227 Documentation of features in Transfers library model is wrong

* Note. Checks have not been implemented for the new constraints validateStructureSpecialization and validateBehaviorSpecialization added in the resolution to issue KERML-43, pending the resolution of issue SYSML2-592.

Resolutions of the following issues were previously implemented in PR #504:

• KERML-182 Update Kernel Semantic Library for validateRedefinitionDirectionConformance
• KERML-184 Update Kernel Model Libraries for validateFeatureValueOverriding constraint
• KERML-186 Update semantic model of invariants for validateExpressionResultExpressionMembership constraint
• KERML-195 Transfer sourceOutput and targetInput directions

Resolutions of the following issues did not require any update to the library model files:

• KERML-175 Natural unnecessary explicit general type declaration
• KERML-176 Base Overview Type
• KERML-177 Legacy, so incorrect, wording in Anything Description
• KERML-178 Anything.self subsetting inconsistent declaration with Base.kerml declaration
• KERML-180 Occurrence Overview Typo

[conradbock]

• ControlPerformances::IfThenElsePerformance, elseCaluse -> elseClause

• Indenting looks off under Links::BinaryLinks, SpatialFrames::DefaultFrameLife.

[seidewitz]

@conradbock

• I corrected the mispelling in the documentation comment for IfThenElsePerformance.
• The indentation being displayed in GitHub depends on whether physical tabs or spaces were entered into the text file by the editor for indentation. The configuration of this has varied. The indentation lines up in an actual editor. This is a general issue, not introduced by the changes in is PR. However, I have updated the Links and SpatialFrames files so that they, at least, both consistently use only spaces for indentation.