fix for StorageList and tests added

gluon/storage.py
StorageList had a recursion error (please check the implementation before committing)

gluon/tests*
added the fix_path module to avoid those ugly lines at the beginning of each test file
added tests for gluon.contenttype and test_fileutils
added tests for missing Storage methods

gluon/tests/__init__.py

@@ -2,14 +2,8 @@ import os, sys
 
 from test_http import *
 from test_cache import *
-
-NOSQL = any([name in (os.getenv("DB") or "")
-             for name in ("datastore", "mongodb", "imap")])
-if NOSQL:
-    from test_dal_nosql import *
-else:
-    from test_dal import *
-
+from test_contenttype import *
+from test_fileutils import *
 from test_html import *
 from test_is_url import *
 from test_languages import *
@@ -25,3 +19,12 @@ from test_web import *
 
 if sys.version[:3] == '2.7':
     from test_old_doctests import *
+
+
+NOSQL = any([name in (os.getenv("DB") or "")
+        	for name in ("datastore", "mongodb", "imap")])
+
+if NOSQL:
+    from test_dal_nosql import *
+else:
+    from test_dal import *