Fixed display of numeric data values
Added test for correct display of numeric data.
Try to stringify anything.
Combine if's.
(#71) Add tests for calling toString on data values

Add a test case for calling the toString() method on data values.
Add documentation for calling toString() on data values
Merge pull request #72 from glittershark/fix-numeric-display

Try to call `.toString()` on all passed data values (Thanks @joneshf and @zeroedin-bill)