Remove support for IE8
Upgrade jQuery. Fix bootstrap file path
Add SASS instructions
Update keyframe mixin.

- ms prefix has never existed
- FF dropped need many versions ago
Move animation mixins into mixins file. Do not import variables twice.
Re-add animations.sass (not a mixin file)
Remove unneeded css file
Take customisations out of switchery vendor file
Remove unneeded css file. Move vendor styles to top