... if it has multiple columns. See commit
d1852047 (DOCX import: set
DontBalanceTextColumns=true for the last section, 2014-07-17) for the
DOCX equivalent of this problem; this just adapts the RTF tokenizer to
dmapper.

Change-Id: Ib30f9b386e204b8b2987832ab17ee0cc53b3f0bc