Combine jimi-c and bcoca's ideas and work on hooking module-utils into PluginLoader.

This version just gets the relevant paths from PluginLoader and then
uses the existing imp.find_plugin() calls in the AnsiballZ code to load
the proper module_utils.

Modify PluginLoader to optionally omit subdirectories (module_utils
needs to operate on top level dirs, not on subdirs because it has
a hierarchical namespace whereas all other plugins use a flat
namespace).

Rename snippet* variables to module_utils*

Add a small number of unittests for recursive_finder

Add a larger number of integration tests to demonstrate that
module_utils is working.

Whitelist module-style shebang in test target library dirs

Prefix module_data variable with b_ to be clear that it holds bytes data

test/integration/targets/module_utils/module_utils_test.yml

@@ -0,0 +1,50 @@
+- hosts: localhost
+  gather_facts: no
+  tasks:
+  - name: Use a specially crafted module to see if things were imported correctly
+    test:
+    register: result
+
+  - name: Check that the module imported the correct version of each module_util
+    assert:
+      that:
+        - 'result["abcdefgh"] == "abcdefgh"'
+        - 'result["bar0"] == "bar0"'
+        - 'result["bar1"] == "bar1"'
+        - 'result["bar2"] == "bar2"'
+        - 'result["baz1"] == "baz1"'
+        - 'result["baz2"] == "baz2"'
+        - 'result["foo0"] == "foo0"'
+        - 'result["foo1"] == "foo1"'
+        - 'result["foo2"] == "foo2"'
+        - 'result["qux1"] == "qux1"'
+        - 'result["qux2"] == ["qux2:quux", "qux2:quuz"]'
+        - 'result["spam1"] == "spam1"'
+        - 'result["spam2"] == "spam2"'
+        - 'result["spam3"] == "spam3"'
+        - 'result["spam4"] == "spam4"'
+        - 'result["spam5"] == ["spam5:bacon", "spam5:eggs"]'
+        - 'result["spam6"] == ["spam6:bacon", "spam6:eggs"]'
+        - 'result["spam7"] == ["spam7:bacon", "spam7:eggs"]'
+        - 'result["spam8"] == ["spam8:bacon", "spam8:eggs"]'
+
+  # Test that overriding something in module_utils with something in the local library works
+  - name: Test that local module_utils overrides facts.py
+    test_override:
+    register: result
+
+  - name: Make sure the we used the local facts.py, not the one shipped with ansible
+    assert:
+      that:
+        - 'result["data"] == "overridden facts.py"'
+
+  - name: Test that importing a module that only exists inside of a submodule does not work
+    test_failure:
+    ignore_errors: True
+    register: result
+
+  - name: Make sure we failed in AnsiBallZ
+    assert:
+      that:
+        - 'result["failed"] == True'
+        - '"Could not find imported module support code for test_failure.  Looked for either foo or zebra" == result["msg"]'