Maintenance release for 2.51 branch

Features:

• Set recommended version Git version to 2.17.1 - PR 5095
• Recheck filter against displayed file name when working in the fileNameOnlyMode mode. - Issue 4991
• Add Atom Editor to Git Config section - Issue 2507

Fixes:

• Repository init dialog shows incorrect location - Issue 5107
• Git-status in the background should use --no-optional-locks - Issue 5066
• Typing 'b' or 'h' into the Diff Filter Files text box doesn't insert the character - Issue 5065
• Customized window size is not kept - Issue 5021
• RTF round-trip bug causes System.ArgumentException: File format is not valid - Issue 5005
• Crash on opening repository in Recent list. - Issue 4549
• Commit index count disapears on refresh - Issue 4483