(\dotable): Don't inherit \rightskip from

(\dotable): Don't inherit \rightskip from
surrounding environment.  Add \leftskip to \hsize in the first
column.  Set \item to \crcr to avoid empty first row.  Prepend
\parskip glue before table.  Set \everycr locally outside of
alignment, don't reset it explicitly in \Emultitable.
From Andreas Schwab.

Also, work on leading commentary in file a bit.