More clever key reassignment in sequence
More clever key reassignment in sequence

	Be more clever when reassigning keys when converting from sequence to str.
	The previous method was just reusing the old keys, in the order of the sequence.
	I.e. if the old keys were
		glou-1 = plop
		glou-4 = truc
	And the conversion was made on ['plop', 'glou', 'truc'] then the result was:
		glou-1 = plop
		glou-4 = glou
		glou-5 = truc
	Thus, we have to check if the element was already assigned a key, and then check if we have enough «room» for the items that were not assigned a key. For example, if the old keys are:
		glou-1 = plop
		glou-4 = truc
	And the conversion is made on ['plop', 'glou', 'truc'] then the result will be:
		glou-1 = plop
		glou-2 = glou
		glou-4 = truc

SmartJog/sjconf,SmartJog/sjconf