Added and then commented out some code that checks for a null file name
passed to the initialize() method.  Commented it out because it really
doesn't do anything but print to the screen, but left it in because I
anticipate needing it later.
Argh--fixed a bug that I introduced in the last commit!  I had a stray
"end".
All but one test now implemented.  Many of them are failing, mostly
related to handling lookup of case variants and variants with leading
or trailing whitespace.  Some other failures are related to exceptional
inputs like empties and nulls.
The calculator.rb and calculator_spec.rb files are intended for
troubleshooting rspec in this project.  They have nothing to do
with the project itself--they are just simple files that should
run fine.
Diff doesn't show any differences here, but git status says that something
needs to be done, so I'm committing.
This is a copy of the same file in the parent directory, put here
to simplify reading it in to initialize a class.  It should be the
same as the file of the same name in the parent directory, but that
will have to be maintained manually.  TODO: Should I replace it with a
link to the file in the parent directory??
Git diff doesn't show any differences in this file, but git status
seems to want me to commit it...
Added a number of new tests and "should"s for a bunch more.