Add --verbose option and use with verilator simulation

	* bin/fusesoc.in (def run): Add --verbose option
	* fusesoc/config.py (class Config): Add class member for --verbose
	option.
	* fusesoc/section.py: Detail compilation and linking commands if
	--verbose flag is given.
	* fusesoc/simulator/verilator.py (class Verilator): Detail verilator
	command if --verbose flag is given.