Docs: Provide Custom-Build instructions

[staabm]

Docs: Provide Custom-Build instructions

[pmb0]

See https://github.com/pmb0/shariff-integration for a custom build example.

[craiq]

big css is because of complete implementation of font awesome
and big js is because of implementation of jquery
the services take the least space
from font awesome you just need very little, but you have to change several lines, when you want to do this.
when you already have jquery, you can use the small js

How to build:
install node.js
run in the shariff-folder with your console:
npm install
grunt build