rename path verification methods to introspection and add NodePath#getSource method

src/babel/traversal/path/README.md

@@ -7,4 +7,4 @@
  - `replacement` - Methods responsible for replacing a node with another.
  - `removal` - Methods responsible for removing a node.
  - `family` - Methods responsible for dealing with/retrieving children or siblings.
- - `verification` - Methodsresponsible for introspecting the current path for certain values.
+ - `introspection` - Methods responsible for introspecting the current path for certain values.

src/babel/traversal/path/introspection.js

@@ -210,3 +210,16 @@ export function referencesImport(moduleSource, importName) {
 
   return false;
 }
+
+/**
+ * Description
+ */
+
+export function getSource() {
+  var node = this.node;
+  if (node.end) {
+    return this.hub.file.code.slice(node.start, node.end);
+  } else {
+    return "";
+  }
+}