Update README.md
re-add slideup.glsl example
Fix wrong note in Sweet Dreams Example

The second to last note of the melody in the sweet dreams example is off by 3 semitones. Easy to tell when compared to the source material ;)
Merge pull request #2 from AaronOpfer/patch-1

Fix wrong note in Sweet Dreams Example
less volume in hello_world + polish sweet_dream
Merge branch 'master' into gh-pages
build