* Rewrite FdEntry reusing as much libstd as possible
* Use the new FdEntry, FdObject, Descriptor struct in *nix impl
* Adapt Windows impl
* Remove unnecessary check in fd_read
Check `host_nread == 0` caused premature FdEntry closure and removal
which ultimately was resulting in an attempt at "double closing" of
the same file descriptor at the end of the Wasm program:
...
fd_close(fd=4)
-> errno=WASI_ESUCCESS
fd_close(fd=4)
-> errno=WASI_EBADF
* Use libstd vectored IO
* Use std:🧵:yield_now to implement sched_yield
* Add logging to integration tests
* Add preliminary support for host-specific errors
* Operate on std::fs::File in path_get on *nix
* Add cross-platform RawString type encapsulating OsStrExt
* Fix Windows build
* Update Travis and README to Rust v1.36
* Remove unused winx::handle::close helper
* Refactor Descriptor into raw handles/fds
* Strip readlinkat in prep for path_get host-independent
* Strip openat in prep for path_get host-independent
* Move ManuallyDrop up one level from Descriptor to FdObject
* Make (c)iovec host fns unsafe
* Swap unwraps/expects for Results in fdentry_impl on nix
* Rewrite fd_pread/write and implement for Win
* Use File::sync_all to impl fd_sync
* Use File::sync_data to impl fd_datasync
* Rewind file cursor after fd_p{read, write} on Windows
* Add fd_p{read, write} tests
* Handle errors instead of panicking in path_get
* Use File::set_len to impl fd_allocate
* Add test for fd_allocate
* Replace all panics with Results
* Document the point of RawString
