Create higher-resolution logo

- Updated SVG to be 667x500 (4:3 aspect ratio)
- Included PNG suitable for embedding for Hello Ruboto (26kb)
Added 4:3 and 16:9 logos

- New SVGs (background extension, translation of image + text)
- Added lightweight PNGs (generated by SVC-Editor online)
As requested by @donV
Revert "Create higher-resolution logo"

This reverts commit 1b51183588394484cb5ee3310952fb92e82cf108.
Re-commit 4:3 logo's PNG
Merge pull request #391 from ashes999/master

Updated SVG logo to be 4:3; generated PNG for 0.11 release