Hack fix so complex capture highlighting doesn't kill Vico.

Right now a capture highlight that contains more than just
a name for the capture group makes Vico enter an
unrecoverable state. We guard for the `name` key being
present in the capture object before trying to use it.

This is a stopgap fix until we implement proper support for
more complex capture highlight definitions.
Compile subpatterns in (beginC|endC|c)aptures syntax segments.

This prepares us for being able to apply these patterns
when syntax highlighting.
Apply patterns when highlighting captures if present.
Merge pull request #66 from vicoapp/complex-capture-highlighting

broken Haskell

capture/beginCapture/endCapture segments can now apply subpatterns to their matches.