---------------------------------------
- xleash:
- Plugins for backends and filters.
- Packaging now supports 3 extras:
- ``xlrd`` for the typical backend plugin,
- ``xlwings`` for the new backend, excel-utils & tests,
- ``pandas`` for filters plugins.
- FIX & rename pandas-filter ``series --> sr`` - did not return a ``Lasso``.
- Always convert xl-ref paths a "local" or "remote" urls to facilitate
backends & use their `url.params` instead of filter `opts`.
- Rename ``io._sheets --> io.backend``.
- xlutils, deps: Upgraded to ``xlwings-0.9.x`` released Aug/2/2016
(see `migration guide <http://docs.xlwings.org/en/stable/migrate_to_0.9.html>`_)
- Dropped util-functions (provided by now `xlwings`) or renamed:
- ``xlutils.get_active_workbook()``
- ``xlutils.get_workbook()``
- ``tests._tutils.xw_Workbook() --> tests._tutils.xw_no_save_Workbook()``
- utils: Add more file/str functions from co2mpas-sampling
(which/where, convpath, convert to/from came_case, publicize norm/abs paths)
- Unfortunately, Travis were down during the release (actually logs did not work),
so TCs fail :-(