JBIDE-17258 BrowserSim: use javaFx web engine for 64bit Windows

implemented, modified preferences page
JBIDE-17234 suggested improvements to dialogs to mention JDK7/8 instead of JRE/JDK 6 + JDK 7

Conflicts:
	plugins/org.jboss.tools.vpe.browsersim/src/org/jboss/tools/vpe/browsersim/ui/messages.properties
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