v0.3.1 (2016/08/19):
    Changed "generator" parameter of getvariants method to "as_generator", just for consistency.

v0.3.0 (2016/08/09):
    Added caching functions for all query types except "fetch_all" if requests-cache is installed.  Can turn request caching on with set_caching(), off with stop_caching().  The cache can be cleared with clear_cache().
    Make "fetch_all" compatible with Elasticsearch v2.x scroll changes.
    Added a "generator" parameter to getvariants (default False).   When True, a generator to all results is returned rather than a list of all results.  This requires much less memory for very large queries (eg vcf file annotation).

v0.2.0 (2015/10/28):
    return None when input vid does not exist for getvariant method.
    raise requests.exceptions.HTTPError when invalid status code returned.
    new "get_fields" method to search for matching field names.
    new "fetch_all" parameter for query method to retrieve large query.

v0.1.2 (2015/08/03):
    renamed get_hgvs_from_vcf to format_hgvs for clarity.
    renamed get_hgvs to format_hgvs_from_vcf for clarity.

v0.1.1 (2015/08/03):
    getvariants and querymany methods now support an iterator as the input (more memory efficient for a large list)
    get_hgvs helper function now takes either filename or file handle and return a generator instead of a list.

v0.1.0 (2015/07/31):
    initial release