Intermittent buggy scrolling on full plots section

[jethror1]

Scrolling on full plots section sometimes is buggy and will jump / not load all plots without scrolling past. The viewport height is currently set dynamically at 75% with scrollY, this along with non fixed row heights seems to be the cause of the issue on it trying to constantly redraw and calculate each row height. Searching still works to allow for viewing plots when scrolling doesn't work correctly.

Switching this to a fixed integer height stops this and correctly displays a loading message when scrolling quickly, or alternatively using pagination

athena/data/templates/single_template.html

Lines 383 to 402 in a6122ee

	<script type="text/javascript" class="init">
	$(document).ready(function() {
	var data = [ $all_plots ];
	$('#fullPlots').DataTable( {
	data: data,
	deferRender: true,
	pageResize: true,
	info: false,
	scrollY: "75vh",
	scrollCollapse: true,
	scroller: true,
	scroller: {
	loadingIndicator: true
	},
	'processing': true,
	'language': {
	'loadingRecords': '&nbsp;',
	'processing': 'Loading...'
	},