Add support for evaluating BOOL and introduce basic logical operators as functions

smnp/runtime/evaluators/bool.py

@@ -0,0 +1,9 @@
+from smnp.runtime.evaluator import Evaluator
+from smnp.type.model import Type
+
+
+class BoolEvaluator(Evaluator):
+
+    @classmethod
+    def evaluator(cls, node, environment):
+        return Type.bool(node.value)