make py lib a self-contained directory again

- move and merge _py/ bits back to py/
- fixes all around

--HG--
branch : trunk

testing/plugin/test_pytest_figleaf.py

@@ -0,0 +1,17 @@
+import py
+
+def test_functional(testdir):
+    py.test.importorskip("figleaf")
+    testdir.plugins.append("figleaf")
+    testdir.makepyfile("""
+        def f():    
+            x = 42
+        def test_whatever():
+            pass
+        """)
+    result = testdir.runpytest('-F')
+    assert result.ret == 0
+    assert result.stdout.fnmatch_lines([
+        '*figleaf html*'
+        ])
+    #print result.stdout.str()