feat colors: Material design color palette with Sass

Create all the colors variants from material design guidelines.
http://www.google.fr/design/spec/style/color.html
chore demo: move demo scss file to demo folder
chore demo: change colors label for better visibility
feat colors: add new colors to default settings
chore demo: remove empty lines from colors scss
chore demo: colors as first css demo
chore demo: notifications as first services demo
chore dist: update
Merge pull request #4 from lumapps/feat/colors

feat colors: material design color palette with Sass