
there are several types of files in here.  first are the report data
processors.  when cbb runs a report, it starts one of these Perl
scripts, passing it the date range and the list of accounts for the
report.  

[currently, the process may fail if there are errors on the command
line, but the return to CBB of this error is inconsistent.  the perl
script should check the command line argements first and if bad,
return an error, but if good, return a status line saying OK or
something.  CBB will therefore always know to look for 1 line which
will come right away from the report/graph]

when the perl script is done, it generates a list of values which it
passes to the actual graphing or printing facility, usually written in
tcl again.  

report [plot script] : description

txn-list.pl : plot running balance
cat-col.pl  : plot movements by categories
cat2-col.pl : plot expenses by category
cat-pie.pl  : plot expenses by category (pie chart)
desc-pie.pl : plot categories by description pie chart


