Version 2.51

Update README.md

Fixing gitextensions#4264: added simplify-merges option when enabling…

… full-history. (gitextensions#4265)

* Fixing gitextensions#4264: added simplify-merges option when enabling full-history.
* Added ShowFullHistory toolbar button.

Version 2.50.02

Version 2.50

2.50RC2

Release date.

Version changed to 2.49.3

Release date set.