The tabularew environment is similar to tabular (LaTeX kernel) but adds
a new command to modify the horizontal alignment in certain circumstances.

It solves the problem of centering multicolumn headings when they are
wider than the text underneath them. (In a tabular environment they are
aligned to the left, even if they contain a "c" in their preamble.)

It is actually a workaround for a (mis)feature of TeX alignment algorithm.

Comments and suggestions are welcome, especially for the user interface.

Diego Saba
diegosaba at gmail dot com
