Merge pull request #57 from dqrobotics/20.04-hotfix1

20.04 hotfix1

Merge pull request #56 from dqrobotics/updating_to_20_04

Adding DQ_SerialManipulatorDH

Merge pull request #52 from dqrobotics/issue51

Renames VrepInterface to DQ_VrepInterface and fixes issue #51

Release 19.10.0