Merge pull request tpaviot#1160 from tpaviot/review/occt770

Port to occt770

Merge pull request tpaviot#1133 from tpaviot/review/occt762

wrapper for occt7.6.2

Prepare release 7.5.1

Set version number to 7.5.0rc1

update generator.log

prepare release 7.4.0

rc1 updates

update README/NEWS for 7.4.0beta2

Merge pull request tpaviot#718 from tpaviot/review/prepare-r740beta

Review/prepare r740beta

Added 3.8 to travis.yml and appveyor, to check if py3.8 is supported