Prepare self for a new visit.

Property definitions

nitc $ PrettyPrinterVisitor :: clear
	# Prepare `self` for a new visit.
	private fun clear do
		tpl = new Template
		current_token = null
		indent = 0
		current_length = 0
		previous_length = 0
		wait_addn = 0
	end
src/pretty.nit:86,2--94,4