Customizable drawers V2

This is a remix of something I've already done, changed wall thinkness to 1.2mm so it will be printable by 0,3 and 0,4mm nozzles and given user more possibilities on layout definition.

Now all files use common parameters defined in 'Parameters.scad'

I got hints from https://www.thingiverse.com/thing:3171891 and adapted to mine

2018-12-17:
- Updated Parameters.scad

2018-12-16:
- Fix nameplate computation (thanks to bernard_maurin for reporting such error)