Concrete `Change` classes: implement structural equality

[mfulton26]

I'm using JaVers to compare two objects in a test. I have some expected changes that I want to remove from the list of changes but ValueChange et. al. do not override the default hashCode/equals so I can't use convenient List methods like in change.removeAll(expectedChanges) after which I would assert that the list of changes is empty.

I took a look at ValueChange and some other concrete Change classes and from what I can tell GlobalId, Atomic, etc. all override the default hashCode/equals.

Can ValueChange et. al. be updated to also support structural equality instead of referential equality (default hashCode/equals)?

[bartoszwalacik]

I think ValueChange could implement equals and hashcode based on left and right values. Diff and all its child objects have to remain immutable. You can came up with a PR if you want.

[bartoszwalacik]

released in 2.0.1