New course logos and banners for course1/2/3.
Fix up /s/ page for non-k-5 scripts.
Automatically built
Improvements to beta pages.
Merge pull request #1057 from code-dot-org/courseimages

Add course images & fix /s/ for non-k-5 courses
Use image_tag properly for /beta.
Merge pull request #1061 from code-dot-org/finished

merge finished to delivered