Use line stacked in mem.json ?

[Joxit]

Why do not you use the lines stacked for memory? "type": "line-stacked"

chronograf/canned/mem.json

Lines 6 to 22 in e2e684b

	"cells": [
	{
	"x": 0,
	"y": 0,
	"w": 4,
	"h": 4,
	"i": "e6e5063c-43d5-409b-a0ab-68da51ed3f28",
	"name": "System - Memory Gigabytes Used",
	"queries": [
	{
	"query": "SELECT mean(\"used\") / 1073741824 AS \"used\", mean(\"available\") / 1073741824 AS \"available\" FROM \"mem\"",
	"label": "GB",
	"groupbys": [],
	"wheres": []
	}
	]
	}

This could be more meaningful given that used + available = total

[nhaugo]

@Joxit any interest in submitting a PR

[Joxit]

Done in #1933