Support for JSR-45 Debug Information

[wasabii]

JSR-45 defines a format by which source information can be included in a class file that extends the SourceFile attribute. It was made for languages other than Java which might distribute source for one class across multiple files. It is used by Kotlin and others, though they vary in how well they conform to the spec.

Such information can be used to augment the symbol writer in IKVM. For one, .NET already supports sequence points that span documents. The JSR-45 information can probably be converted to this.