[lmi] New ledger columns

[Greg Chicares]

Experience rating has been more difficult to test than it should
be. To make it easier, it is necessary to add new report columns;
doing that provides a good opportunity for removing or renaming
various other columns:
  
http://savannah.nongnu.org/cgi-bin/viewcvs/lmi/lmi/ledger_base.cpp.diff?r1=1.5&r2=1.6
Regression-test output gives values for all columns in an order
sorted alphabetically within each 'basis', so this creates an
obstacle to comparison, which is best obviated by running the
test suite with only that file changed, then comparing the
results after making other changes, as the 20051009T2247Z
'ChangeLog' entry describes.

Ledger columns--columns in the ledger class--are exactly those
columns you see in '.test' output. They're written to '.xml'
output used for printing. For supplemental reports, they're
potentially available; making them actually available requires
making them known to the GUI. For the Ctrl-Shift-S spreadsheet,
they're potentially available; making them actually available
requires a programming change.

Both new experience-rating columns have been added to the
Ctrl-Shift-S spreadsheet, making experience rating easier to
validate. It now appears that the projected mortality charge
has never reflected the third point in the specifications
quoted here:

///   the just-completed year's EOY (DB - AV), times
///   the about-to-begin year's COI rate times twelve, times
///   the proportion surviving into the about-to-begin year, times

but at least now we have handy tools for investigating that.

For supplemental reports, no new column has been made available,
but two old columns have been replaced by another:
  
http://savannah.nongnu.org/cgi-bin/viewcvs/lmi/lmi/mc_enum_types.xpp.diff?r1=1.8&r2=1.9
because the former distinction begged a question whose answer
could hardly be comprehended (it's given in the comment block
expunged here:
  
http://savannah.nongnu.org/cgi-bin/viewcvs/lmi/lmi/ledger_variant.cpp.diff?r1=1.10&r2=1.11
). This change affects any saved input files that used either
of the former columns; it's not likely that any end user would
be affected, so undertaking extra work to provide backward
compatibility here does not seem justified. Any testdecks
affected should be modified manually.

I'm not entirely sure what effect these changes have on
printing, but the '.xsl' files probably need to updated. The
copies in cvs are ancient; perhaps this is a good time to
start keeping them current in cvs.

To tackle this defect report
  https://savannah.nongnu.org/bugs/?func=detailitem&item_id=13787
in general requires adding, deleting, or renaming various columns
aside from those discussed here. The present change demonstrates
the side effects of such changes, and those side effects militate
against piecemeal changes. To avoid compatibility issues, we
should strive to present a full palate of valid columns with
clear names before end users employ supplemental reports widely.