Align the Mimes! - fixes #225

Previous mimetypes were based on scaled version of the 48px size design. This pull request changes the following things:

* Realigned design for 16px, 22px, 24px, and 32px
* Remove text labels from sizes 16px, 22px, and 24px
* Minor corrections for 48px
* Switched 64px, 128px and 256px to be a scaled version of the new 32px