Transformer should process multiple entry-points even when it encounters errors

This issue was extracted from issue #37, submitted by @zoechi.

The issue is that the transformer stops with an error message whenever it encounters a program that contains constructs which prevent the transformation from being completed (e.g., if the super initializer in a subclass of class `Reflectable` passes a non-const argument), but it would be more useful if it were to emit the error message such that the programmer knows that one of the entry points could not be transformed (the error message should of course contain information about the location in the code that causes the transformation to stop), and then proceed to transform the remaining entry points.