This is a bug-fix release, but it's big enough I'm giving it a minor
version.
- Fix a very old bug in which DDL rows were writing the start of the
row intomaxwell.positions, leading to chaos in some scenarios where
maxwell managed to stop on the row and double-process it, as well as to
a few well-meaning patches. - Fix the fact that maxwell was outputting "next-position" instead of
"position" of a row into JSON. - Fix the master-recovery code to store schema that corresponds to the
start of a row, and points the replicator at the next-position.
Much thanks to Tim, Likun and others in sorting this mess out.