Fixing annotation icon issues

This patch makes sure that the annotation icons are properly scaled in IE (because currently IE does not resize the annotation icons, but clips them instead). This has been resolved by setting the `viewBox` property in the SVG files. This also improves the rendering in Firefox.

On top of that, this patch removes the width scaling which caused some of the icons to look blurry in all browsers.

With this patch, all browsers display the SVG annotation icons correctly and in the same way.

Fixes #3650 and #2963.

Comparison:

![naamloos-1](https://f.cloud.github.com/assets/1993262/1098763/e2b950c2-1727-11e3-8b1a-0a2af0f694ed.jpg)