[GSoC 2018 - TrackGit] Progress Report 12

This is the twelveth progress report for TrackGit project. I did the following in last week:

Implemented Log Viewer

I implemented a log viewer in TrackGit. It shows a window with the commits in the repository so far. Link to commit.

The following screenshot shows the log viewer:

I also added tests for the log command. Link to commit.