added organizations app to more than one user can see dataclips
some adjusts on dataclips and database
fix database test
adjus model relation
now that clips belongs to a organization too we don't need to use manager by_organization anymore
added __init__.py inside tags migrations folder
whitespace
improved README
added some missing __init__.py
Removed u prefix from strings and use from __future__ import unicode_literals. Added @python_2_unicode_compatible to several classes. Removed unicode calls and encoded unicode where we needed bytestrings