Add lexlocation to ActionDefs introduced by mu.

[Issue: #301]
Test and result for issue 301.

[Issue: close #301]
Only create exists exp if the bindlist is nonempty.

[Issue: #298]
Add test and result for issue 298.

close #298
Update test results following fix of #298

[Issue: ]
Merge commit 'fa2286da079dfd01d070ca7964c5f802e17fd931' into rjp