adds simple nil specs

core/nil/control-flow-spec.io

@@ -0,0 +1,13 @@
+describe("nil Control Flow",
+  it("evaluates the argument to ifNilEval",
+    nil ifNilEval(42) verify(== 42)
+  )
+
+  it("returns false when receiving and",
+    nil and(42) verify(== nil)
+  )
+
+  it("returns the argument to or",
+    nil or(42) verify(== 42)
+  )
+)

core/nil/nil-spec.io

@@ -0,0 +1,5 @@
+describe("nil",
+  it("has a single instance",
+    nil clone uniqueId verify(== nil uniqueId)
+  )
+)