Fix annotations (icons, colors, refreshing after commit).

Remove line coloring for annotations. 
Add icons for all annotations. 
Reload annotations on view focus, so annotations can be refreshed after commit.

For icon styling (different colors), in theme you can set:

<dict>
        <key>name</key>
        <string>Git Modified Line</string>
        <key>scope</key>
        <string>git.changes.x</string>
        <key>settings</key>
        <dict>           
            <key>foreground</key>
            <string>#49B9F5</string>
        </dict>
    </dict>
    <dict>
        <key>name</key>
        <string>Git Added Line</string>
        <key>scope</key>
        <string>git.changes.+</string>
        <key>settings</key>
        <dict>
            <key>foreground</key>
            <string>#15ED3D</string>
        </dict>
    </dict>
    <dict>
        <key>name</key>
        <string>Git Remove Line</string>
        <key>scope</key>
        <string>git.changes.-</string>
        <key>settings</key>
        <dict>
            <key>foreground</key>
            <string>#A72822</string>
        </dict>
    </dict>