v0.5.0 (2019/11/26):
    Support adding license url from datasource metadata. 

v0.4.0 (2019/08/07):
    Improve a few test cases and test utility organization.

v0.3.0 (2019/05/01):
    Support Elasticsearch 6.x as the backend, Elasticsearch 2.x is no longer supported.
    Require Python>=3.4.
    Removed httplib2 dependencies.
    Changed "msgpack=1" query parameter to "format=msgpack".
    Support "format=yaml" return format.
    Support "format=html" return format (useful for demo purpose).
    Support always_list and allow_null query parameters.
    Support optional "q=__any__" to return random docs.
    Redesigned test helper.
    Other accumulated improvements at https://github.com/biothings/biothings.api/commits/v0.3.0

v0.2.x
    Not been released to PyPI.

v0.1.0 (2017/07/22):
    initial release
v0.5.0 (2019/12/02):
    Support adding license url from datasource metadata. 
    Improve concurrent performance with async elasticsearch transport client.

v0.4.0 (2019/08/07):
    Improve a few test cases and test utility organization.

v0.3.0 (2019/05/01):
    Support Elasticsearch 6.x as the backend, Elasticsearch 2.x is no longer supported.
    Require Python>=3.4.
    Removed httplib2 dependencies.
    Changed "msgpack=1" query parameter to "format=msgpack".
    Support "format=yaml" return format.
    Support "format=html" return format (useful for demo purpose).
    Support always_list and allow_null query parameters.
    Support optional "q=__any__" to return random docs.
    Redesigned test helper.
    Other accumulated improvements at https://github.com/biothings/biothings.api/commits/v0.3.0

v0.2.x
    Not been released to PyPI.

v0.1.0 (2017/07/22):
    initial release
Add async es to this update
Add async es to this update
