Remove Schema::is* methods

These methods are not really used anywhere, and if they are, they can be
replaced with a call to Schema::nodeType. No reason to keep them. I had
to implement StaticSchema::nodeType(std::string) because of
presenceContainerPath_class, but that's ok.

Change-Id: Ia27f6aa1f1cd098f087767365cb6a706c255c206
diff --git a/src/sysrepo_access.cpp b/src/sysrepo_access.cpp
index 3af5f79..3278766 100644
--- a/src/sysrepo_access.cpp
+++ b/src/sysrepo_access.cpp
@@ -196,7 +196,7 @@
             return;
         for (unsigned int i = 0; i < items->val_cnt(); i++) {
             auto value = leafValueFromVal(items->val(i));
-            if (m_schema->isLeafList(items->val(i)->xpath())) {
+            if (m_schema->nodeType(items->val(i)->xpath()) == yang::NodeTypes::LeafList) {
                 res.push_back({items->val(i)->xpath(), special_{SpecialValue::LeafList}});
                 std::string leafListPath = items->val(i)->xpath();
                 while (i < items->val_cnt() && leafListPath == items->val(i)->xpath()) {