Adapt to released numpy

Update version and changelog.txt

Merge pull request #67 from vasole/lower_bound

Add missing include.

Merge pull request #61 from vasole/release

Prepare release.

Merge pull request #49 from vasole/changelog

Clearer changelog text.

Update changelog.txt

Merge pull request #41 from vasole/3.8

Change minor version.

Merge pull request #40 from vasole/1.1.7

Prepare 1.1.7 release

Merge pull request #31 from PiRK/release1.1.6

Release1.1.6

Update version and changelog.txt