Adapt for Iterable.indexes rename

Also, I only ever used the first index. Huh.
More ceylonic code in formattingFile_meta

Not that it matters since that file is _so_ outdated right now (#20).
Make ceylon.test import optional

It’s only needed for the tests (#45); in a release build, I indend to
remove the import completely, but in case I forget, it shouldn’t matter.