expr simplification: step 1

* Fix wrong catchClause code & test 7
* Fix testsuite PNG names misaling of 44.png
* Remove '=' to allowed def separator
* s/last/expr/g in the expr block
* set functionCall precedence to first of expr
* move lastOnly to last of exprMax
* seqExprs : expr+ ;
* exprA : expr ;
* exprM : exprMax ;