[refs #115] Calculate the differences between the setup in the last update call and the current board setup, can be used to display the missing or faulty stones on the board if a move was illegal
Revert "Merge pull request #108 from augmented-go/Go_Scanner"

This reverts commit 7bac7d63b22904e5af69e673d29bb1b3ac07c366, reversing
changes made to ae87d25505f12871bcda91b2bc35efc752a2a9e9.

cause of the scanner bug i could not debug
refs 115 - Implemented a red circle that is shown around the stones that differs from the real board. So all differences between real board an virtual board are shown on the virtual board.
closes #115 - Implemented the red circle around the differing stones
(commited first without # sorry)
refs #115 added/edit some comments
refs #115 - Quick fix for the crash if go_game is null
[ref #115] There aren't differences between the real and internal board if there was a valid move!
Revert "Revert "Merge pull request #108 from augmented-go/Go_Scanner""

This reverts commit c612107ed5e028bc8afc3dfbddc04161a5a88ca5.
Merge remote-tracking branch 'remotes/origin/master' into #115_display_differences

Conflicts:
	Go_Backend_Unittest/backend_test.cpp
Merge branch 'master' into #115_display_differences

Conflicts:
	Go_GUI/GUI.cpp
Merge pull request #136 from augmented-go/#115_display_differences

#115 display differences