Allow connection endpoints for list nonterminals

...rg/jastadd/ragconnect/tests/list/ListIncrementalTest.java

...ava/org/jastadd/ragconnect/tests/list/ListManualTest.java

...d/ragconnect/tests/singleList/AbstractSingleListTest.java

...agconnect/tests/singleList/SingleListIncrementalTest.java

...add/ragconnect/tests/singleList/SingleListManualTest.java

...ests/singleListVariant/AbstractSingleListVariantTest.java

...eListVariant/SingleListVariantIncrementalVariantTest.java

...singleListVariant/SingleListVariantManualVariantTest.java

...a/org/jastadd/ragconnect/tests/tree/AbstractTreeTest.java

...rg/jastadd/ragconnect/tests/tree/TreeIncrementalTest.java

...ava/org/jastadd/ragconnect/tests/tree/TreeManualTest.java

...ests/treeAllowedTokens/AbstractTreeAllowedTokensTest.java

...s/treeAllowedTokens/TreeAllowedTokensIncrementalTest.java

.../tests/treeAllowedTokens/TreeAllowedTokensManualTest.java