Show checkboxes beside files and commit message textbox at all times.

[AndreAngelantoni]

Currently, one must click on Commit changes before one sees the checkboxes beside each modified file and the Commit message textbox.

Further, after clicking the button, all the check boxes are checked. If one wants to commit only one file, one must uncheck the unwanted files.

A better workflow is:

1. Show the checkboxes all the time (like Git Tower does).
2. Show the Commit message box all the time (ditto Git Tower).
3. Check the file(s) to commit.
4. Type commit message or Generate Message button (which are already visible).
5. When step 4 happens, Commit button becomes active.
6. Click Commit.

This workflow seems to me to be the most efficient way to make commits and is especially nice when making multiple commits in a row.