[Info Bubble] Refine positioning, add comments

Refine positioning to behave correctly when mouse is on
right and/or lower part of screen; listen for scope
destruction to avoid cases where an element is removed
before mouseleave is ever called. WTD-884.

platform/commonUI/inspect/res/bubble.html

@@ -1,4 +1,4 @@
-	<div class="t-infobubble s-infobubble l-infobubble-wrapper {{bubble.bubbleLayout}}">
+	<div class="t-infobubble s-infobubble l-infobubble-wrapper {{bubble.bubbleLayout}}" style="position: relative;">
 		<div class="l-infobubble">
 			<div ng-show="bubble.bubbleTitle.length > 0"
 				 class="title">