Update Soda Dark with new folder and spinner features
Update Soda Light with new folder and spinner features
Update README with details on folder icons
Clean up trailing spaces in theme files.
Change appearance of tabs of modified files.

The 'modified' icon was removed in both the light and dark theme.
A setting for the highlighting of modified tabs (both active and
inactive) has been introduced.
Change Command Palette highlighting color.
Merge branch 'customizations' of github.com:mundry/soda-theme into customizations