Variety of changes to JS front end.

- crash fixes
- small enhancements to prologue and preamble
- tighter handling of timeouts during CG construction
Merge branch 'master'

Conflicts:
	com.ibm.wala.cast.java/src/com/ibm/wala/cast/java/loader/JavaSourceLoaderImpl.java
	com.ibm.wala.cast.js.rhino.test/harness-src/com/ibm/wala/cast/js/test/TestSimpleCallGraphShapeRhino.java
	com.ibm.wala.cast.js.rhino.test/harness-src/com/ibm/wala/cast/js/test/TestSimplePageCallGraphShapeRhino.java
	com.ibm.wala.cast.js.rhino.test/harness-src/com/ibm/wala/cast/js/test/TestSimplePageCallGraphShapeRhinoJericho.java
	com.ibm.wala.cast.js.rhino.test/harness-src/com/ibm/wala/cast/js/vis/JsViewerDriver.java
	com.ibm.wala.cast.js.test/harness-src/com/ibm/wala/cast/js/test/TestSimpleCallGraphShape.java
	com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/loader/JavaScriptLoader.java
	com.ibm.wala.cast/source/java/com/ibm/wala/cast/tree/CAstEntity.java