prepare 4.0.4 release

prepare 4.0.3 release

Preparations for 4.0.2 release.

Associated with release 4.0.1 on March 13, 2019.

Associated with release 4.0.0 on September 27, 2018

Associated with NuGet release 4.0.0-rc1 on May 22, 2018

Associated with Unity version 3.5.0 publicly released on October 3, 2017

Associated with NuGet pre-release 3.1.0-alpha published on May 2, 2017

Associated with NuGet release 3.0.2 on April 21, 2017

Associated with version 3.0.1 released on March 6, 2017