0.3.0-alpha.15

0.3.0-alpha.15 - 2019-4-26

• Updated to stabilized futures_api.
• Removed StreamObj, cautioned against usage of FutureObj.
• Changed StreamExt::select to a function.
• Added AsyncBufRead and AsyncSeek traits.
• Expanded trait impls to include more pinned pointers and ?Sized types.
• Added future::Fuse::terminated constructor.
• Added never_error combinator.
• Added StreamExt::enumerate.
• Re-added TryStreamExt::{and_then, or_else}.
• Added functions to partially progress a local pool.
• Changed to use our own Either type rather than the one from the either crate.