Merge remote-tracking branch 'origin/master' into release, conflicts resolved

Conflicts:
	cms/envs/common.py
	common/lib/xmodule/xmodule/seq_module.py
	lms/envs/common.py
	requirements/edx/edx-private.txt

lms/envs/acceptance.py

@@ -45,7 +45,6 @@ MODULESTORE = {
         'ENGINE': 'xmodule.modulestore.mixed.MixedModuleStore',
         'OPTIONS': {
             'mappings': {},
-            'reference_type': 'Location',
             'stores': {
                 'default': {
                     'ENGINE': 'xmodule.modulestore.mongo.MongoModuleStore',

lms/envs/bok_choy.py

@@ -4,7 +4,7 @@ Settings for bok choy tests
 
 import os
 from path import path
-from xmodule.x_module import prefer_xmodules
+from xmodule.modulestore import prefer_xmodules
 
 
 CONFIG_ROOT = path(__file__).abspath().dirname()  #pylint: disable=E1120

lms/envs/cms/dev.py

@@ -32,7 +32,6 @@ MODULESTORE = {
     'default': {
         'ENGINE': 'xmodule.modulestore.mixed.MixedModuleStore',
         'OPTIONS': {
-            'reference_type': 'Location',
             'mappings': {},
             'stores': {
                 'default': {