bump version to 0.6.12

relax version requirement on future and bump to 0.6.7

version bumped to 0.6.6

version bumped to 0.6.5

version bumped to 0.6.3

version bumped to 0.6.2, new authors file

Closes danicarrion#14, wrong datetime detection when serializing reso…

…urces

Closes danicarrion#4, Python 2 support

Version bumped to 0.5.0