io update

This release doesn't change any underlying iopipe functionality, but removes the basic IODev streaming class in iopipe. Instead, one should use Martin Nowak's std.io library for low-level io.

This release is ONLY supported using dmd 2.080.1 or later.

The prior low-level functions are switched to being aliases to std.io, but will be removed in one of the next versions, probably v0.1.2.