Quick trivial refactor of the row adding logic in DataView.
Changing namespace from polyfill (which this version is decidedly *not*) to shim.

This *replaces* System.Data objects; it doesn't check for existence and then fill in only if System.Data objects don't exist.  I might still use this shim to create a true polyfill later, but I think this code fits in a shim namespace more naturally anyhow.

Also minor whiteapce cleanup.  Lots of tabs to spaces.