Enable keyboard and mouse input testing in Travis.
Merge pull request #47 from DO-CV/test-keyboard-mouse-input

Add functional tests for keyboard and mouse input.
Merge remote-tracking branch 'origin' into HEAD
Remove spurious line break.
Merge pull request #48 from DO-CV/test-sleep-functions

[MAINT] Add functional tests for sleep functions.
Merge remote-tracking branch 'origin' into maint-update-readme-md
Merge pull request #49 from DO-CV/maint-update-readme-md

[MAINT] Show Travis CI on top of `README.md`.
Merge remote-tracking branch 'origin' into maint-add-copyright-notice
Remove duplicate test in `CMakeLists.txt`.