[FIX] ir_qweb: css asset: use which to find lessc and sass

Also, use lessc.cmd instead of lessc on Windows. It allows to run
lessc command with only nodejs and the less module (no cygwin).
[ADD] Website_quote: Added a functionality to print web quoatation as pdf. [IMP] Improved style of snippets and web quoatation to handle smaller viewports.