at least the test case seems to work, now left is pretty much mapping
the options and the path handling.

accidentially commited a dangling closing brace.

still need to figure out the Send + Sync + 'static bound, issue is with
Sync, which might come from the refs used, get_block(&cid)..

this required some unsafety to be able to present the Stream as Send +
Sync + 'static as required by hyper. not 100% sure if that pin_project
is ok to do, but the only interfaces exposed are callable as futures so
it shouldn't be too bad.

this is required to have multiple paths.

I had not originally noticed that we need to do the walk from multiple
paths.

also, this should be done when expanding the nodes, not at this stage.

originally it was easier to write everything to the same file, but it
gets difficult to read after 1000 lines. while reorganising stuff into
more tight modules, some direct calls were changed not to be needed,
like RefsOptions creating the EdgeFormatter; the EdgeFormatter is not
created in the refs function itself.

chopped off parts:

 * RefsOptions stuff to refs/options.rs
 * EdgeFormatter and the string format to refs/format.rs
 * Unshared to refs/unshared.rs
 * HandledErr StreamResponse to refs/support.rs

the situation is not good, as it would make sense to re-export libipld
from ipfs as parts are already re-exported but with strange names.

kept the return value as a stream. it'll at least save us the trouble of
concatenating all of the values into a big vector.