Added create size mode (i.e: 'create 1GB')
Added create size mode (i.e: 'create 1GB')

Conflicts:
	lib/program.js

ebfe/scaleway-cli,QuentinPerez/scaleway-cli,QuentinPerez/scaleway-cli,ebfe/scaleway-cli,QuentinPerez/scaleway-cli,ebfe/scaleway-cli