Fix full elimination vs. detectable elimination inconsistency in halflife for lipid soluble

[dgets]

This is to be completed en route to #56.

After getting the bit coded into the halflife routines for detectable and full elimination target date/times, it seems that there must be a bit of inconsistency in the formulas that I'm using. I was told by one of my doctors that full elimination of a substance is normally counted as 5.7 * halflife. Unfortunately, at least in the case of THC, this means that complete elimination takes less time than detectable elimination.

This is, no doubt, due to the fact that the halflife for delta-9 THC is so short, and the fact that it's actually THC-COOH, a secondary or tertiary byproduct of the metabolism, that is tested for. So something needs to at least be coded into the view/template to check and see if full elimination is prior to detectable elimination and print an explanatory message to the user.

It'd be really nice to have a table of secondary/tertiary metabolites that come into play, but that's really not feasible at this point in the game.

[dgets]

The best road to this, I think, is through #58, and by adding documentation regarding what exactly the information being conveyed actually means.