Release version 0.15.3 (#116)

Merge pull request #114 from aleivag/release-0.15.2

Release version 0.15.2

Merge pull request #109 from aleivag/document-wait-for-activation

Document cwd and wait_for_activation parameters in pystemd.run

Merge pull request #108 from aleivag/new_release

new_release_0.15

Merge pull request #103 from aleivag/release014

release 0.14.0

Merge pull request #100 from aleivag/uptdae-in-release

add apt-get update to release

Merge pull request #97 from aleivag/user_mode

enable user_mode in futures

Merge pull request #86 from aleivag/allpyi

selecting all .pyi files

Merge pull request #84 from aleivag/givingbackinstallrequires

adding back the requirements to setup.py

Merge pull request #82 from aleivag/more.unit.services

adding extra propertied for unit signatures