build.gradle: version 2.5.0 (release), add objectboxVersionNumber and…

… objectboxVersionRelease to simplify release process

Merge branch 'v2.4.1'

Merge branch 'v2.4.0'

prepare 2.4.0 RC

2.3.4

2.3.3

remove obsolete test testGetAll2AfterGetAndRemove

2.3.0

README.md: 2.2.0

2.1.0-2018-08-16