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/test_dal.py

@@ -15,40 +15,17 @@ try:
 except:
     from io import StringIO
 
-def fix_sys_path():
-    """
-    logic to have always the correct sys.path
-     '', web2py/gluon, web2py/site-packages, web2py/ ...
-    """
+from fix_path import fix_sys_path
 
-    def add_path_first(path):
-        sys.path = [path] + [p for p in sys.path if (
-            not p == path and not p == (path + '/'))]
-
-    path = os.path.dirname(os.path.abspath(__file__))
-
-    if not os.path.isfile(os.path.join(path,'web2py.py')):
-        i = 0
-        while i<10:
-            i += 1
-            if os.path.exists(os.path.join(path,'web2py.py')):
-                break
-            path = os.path.abspath(os.path.join(path, '..'))
-
-    paths = [path,
-             os.path.abspath(os.path.join(path, 'site-packages')),
-             os.path.abspath(os.path.join(path, 'gluon')),
-             '']
-    [add_path_first(path) for path in paths]
-
-fix_sys_path()
+fix_sys_path(__file__)
 
 #for travis-ci
-DEFAULT_URI = os.environ.get('DB', 'sqlite:memory')
+DEFAULT_URI = os.getenv('DB', 'sqlite:memory')
 
 print 'Testing against %s engine (%s)' % (DEFAULT_URI.partition(':')[0], DEFAULT_URI)
 
 from dal import DAL, Field, Table, SQLALL
+from gluon.cache import CacheInRam
 
 ALLOWED_DATATYPES = [
     'string',
@@ -564,9 +541,8 @@ class TestMinMaxSumAvg(unittest.TestCase):
         db.tt.drop()
 
 
-class TestSelectCache(unittest.TestCase):
+class TestCacheSelect(unittest.TestCase):
     def testRun(self):
-        from cache import CacheInRam
         cache = CacheInRam()
         db = DAL(DEFAULT_URI, check_reserved=['all'])
         db.define_table('tt', Field('aa'))
@@ -1459,7 +1435,6 @@ class TestQuoting(unittest.TestCase):
                 db._adapter.types[key]=db._adapter.types[key].replace(
                 '%(on_delete_action)s','NO ACTION')
 
-                
         t0 = db.define_table('t0',
                         Field('f', 'string'))
         t1 = db.define_table('b',