Report error on code size overflow, log method name.

We used to silently skip class files that would exceed the JVM's size limits.
While rare, this should still be an error.

While I was at it, also included the name of the offending method.

This exercise has me convinced we must create scala-asm, a nice Scala wrapper of asm.
semicolons, null pointer exceptions, no type inference to speak of -- I CANNOT LIVE LIKE THIS

review by @retronym