Add VSToolkit and AnimatedTransition as git submodules in ext/

Commands used:

  git submodule add \
    "git@github.com:vinisketch/VSToolkit.git" \
    ext/VSToolkit

  git submodule add \
    "git@github.com:dthevenin/AnimatedTransition.git" \
    ext/AnimatedTransition
Remove update_lib.sh script replaced with git submodules
Update example to reference CSS and JavaScript from git submodules
Merge pull request #3 from dthevenin/submodules

Submodules