Add constructor that takes a Throwable to eliminate redundant code from callers.

git-svn-id: http://google-refine.googlecode.com/svn/trunk@2518 7d457c2a-affb-35e4-300a-418c747d4874

main/src/com/google/refine/expr/EvalError.java

@@ -56,6 +56,11 @@ public class EvalError implements Serializable, Jsonizable {
         this.message = message;
     }
  
+    public EvalError(Throwable throwable) {
+        this.message = throwable.toString();
+    }
+    
+ 
     @Override
     public String toString() {
         return this.message;