Merge pull request python-xlib#155 from vasily-v-ryabov/prepare_0_26_…

…clean

Prepare 0.26 release

Merge pull request python-xlib#138 from vasily-v-ryabov/prepare_0_25

Bump version in __init__.py

python-xlib 0.24

python-xlib 0.20

bump version to 0.19

bump version to 0.18

bump version to 0.17