Do general bug fixes on Vigil.

Bug fixes include:
* Complain about failing to open a source file.
* Complain about no main() function definition.
* Make it also complain about exceptions which do not inherit from 'Exception'.
* Have better regexes for punishing functions, which removes bugs with delimiting.

Bugs:
I HAVE NOT TESTED THIS VERSION FOR BUGS ENOUGH.
Expect updates.

Limitations:
* It will fail to punish bad code outside a function definition. It is disallowed by language spec but you can't enforce it.

	modified:   vigil
Remove some debug prints.