Made all unit abbreviations and text super/sub-scripts un-italicized with `\mathrm`, as only the labels towards the end of the file did this consistently.  Left out the `M` in `M_{\odot}` as it could go either way.  Also left out the subscript `JL` that appears on some variables, as I'm unsure of its exact meaning, and suspect italics might be appropriate here.  Also left out H/L/V/E as I can see the italics looking better for single-letter detector names.