add pyfs service
code clean
add pyfs service
code clean
fix test case for pyfs
Merge branch 'danielli/pyfs' of https://github.com/edx/edx-platform into danielli/pyfs
Merge pull request #4889 from edx/danielli/pyfs

Adds pyfilesystem service from XBlocks to edx-platform
Revert "Update opaque-keys library to use block_id for html_id for new keys."
Merge pull request #4964 from edx/revert-4960-split/html_id

Revert "Update opaque-keys library to use block_id for html_id for new k...
Make sure that the currently-set language is the
one that shows on the left sidebar if no language
preference exists.

ECOM-135
Update opaque-keys library to use block_id for html_id for new keys.
Catch more places where get_children was giving us version aware references.
LMS-11237
Merge pull request #4966 from edx/split/html_id

Update opaque-keys library to use block_id for html_id for new keys.
Use opaque_keys w/ model vars not parsing of url
to generate url.
LMS-11209
JS regex's need to escape special chars
LMS-11260
Pin coffee-script version to 1.6.1.
BLD-1226: enable 'delete_inactive_group' test.
Merge pull request #4970 from edx/anton/enable-bok-choy-test

Enable Bok Choy split test.
Add test for at least one group before saving a group configuration
Merge pull request #4959 from edx/diana/set-cur-lang

Make sure that the currently-set language is the one that shows on the left sidebar if no language  preference exists.
Merge pull request #4973 from edx/tim/single-group-is-ok

Update test_group_configuration_validation on single group allowed