[Frontend] Mods to allow plot tick labels to ellipsis to left

open #337
Tick label strings are now reversed in their char order in
PlotTickGenerator.js, then reversed again via CSS in
_plots-main.scss. This forces the browser to clip the label
at the left 'start' side, rather than the end, resulting in
the least significant portion of the label getting clipped.

platform/commonUI/general/res/sass/plots/_plots-main.scss

@@ -243,6 +243,8 @@ $plotDisplayArea: ($legendH + $interiorMargin, 0, $xBarH + $interiorMargin, $yBa
 
 .gl-plot-tick,
 .tick-label {
+    direction: rtl;
+    unicode-bidi:bidi-override;
 	font-size: 0.7rem;
 	position: absolute;
 	overflow: hidden;