JBIDE-17244 BrowserSim: Make able to use javaFx web engine on Linux if WebKit is not installed

implemented
Cordovasim: possible NPE fix(showing error message when no suitable jvm)
Merge pull request #40 from kmarmaliykov/JBIDE-17244

JBIDE-17244 BrowserSim: Make able to use javaFx web engine on Linux if WebKit is not installed