preparing v0.13 release

Merge pull request sentinelsat#206 from Fernerkundung/master

v0.12.2

Merge pull request sentinelsat#167 from Fernerkundung/v0.12.1

release v0.12.1

Merge pull request sentinelsat#151 from Fernerkundung/master

release v0.12

Merge branch 'master' of https://github.com/sentinelsat/sentinelsat

0.10 release