Treat pre E as constant if E is constant
Add -xml_to_stdout flag
Abstract away direct outputs to System.out
Merge branch 'master' into function

Conflicts:
	jkind/src/jkind/analysis/NodeDependencyChecker.java
	jkind/src/jkind/analysis/StaticAnalyzer.java
	jkind/src/jkind/analysis/WarnUnguardedPreVisitor.java