Toolbar Styling improvements PR

Several toolbar style improvements:

- Height of the toolbar is now 40px (non-retina).
- Background-color is now white #fff by default, and customizable.
- The spacing between all toolbar icons has been removed.
- The toolbar's border-top and divider color has been changed to #c8c8c8
- The toolbar icons normal color is now #7c7c7c and customizable.
- The toolbar divider line is 28px tall (non-retina), and centered.
- Active items are now tinted #0087be (the line that comes up below the icons too).
- The toolbar now collapses when editing the title, since styles can't be used.
Yep. I think its best to use either the stock RGB methods or, preferably, the color methods from WPStyleGuide.  The smaller DTCoreText's footprint is across our codebase the easier it will be to migrate away from it later.