utility function for creating observables for closeable resources
switch from AutoCloseable to Closeable for java 6.
UnsafeFunc0 now extends Callable.
Merge pull request #1282 from abersnaze/closeable

utility function for creating observables for closeable resources
Use Subscriber.onStart as idiomatic backpressure start point
flatMapAsync test was non-deterministic
Ignoring non-deterministic test

... until someone can figure it out.

This code is far less important now since it is no longer used by merge.
Merge pull request #1417 from benjchristensen/onStart

Proposal: Subscriber.onStart
Version 0.19.6
'rxjava-contrib:rxjava-scalaz'