working on vertex shader sections
added vertex shader intro lesson
added entry in exercises.json
Merge branch 'vert-0'
remove stuff on point sprites and front facing
modify lesson plan and first frag shader exercise
working on datatype lesson
rough sketch of lesson 1
polished up lesson 0 a little bit
fleshed out lesson-1 a bit more thoroughly
mandelbrot demo works now
README.md
fixed bug in frag-0
renamed intro lessons
change to 1 based numbering scheme
started work on vert-2
merged in testing code for intro-1