Figure out why dataview data_summary page isn't accessible now

[dgets]

Something since commit 80366e9 has broken my ability to enter the dataview:data_summary view. I can't for the life of me track it down right now, though. I've tried out every commit between here and there, and even back further, and none of the checkouts are resulting in the functionality returning. Which is funny, being as it just stopped within the last 2 hours here. Whatever broke I didn't notice until I was working on #109 and refreshed the view to make certain that the fix worked.

NoReverseMatch at /dataview/2/
Reverse for 'halflife' with arguments '('',)' not found. 1 pattern(s) tried: ['dataview\/halflife\/(?P<sub_id>[0-9]+)\/$']

is what the Django server is telling me. Not so sure that I believe it this time around.

Either way, I think I'm getting pretty burnt on working on this for the night, probably going to hang it up for now and take over with fresher eyes again tomorrow.

[dgets]

So for some reason this issue appears to be happening when there aren't enough substances or usages added for the current user. Doing more testing now.

[dgets]

Three usages is the minimum and this page starts to render the template correctly. Up until that point it horks on the halflife url wherever it is found.

[dgets]

NOTE: While working on #126, this has popped up again. Clearly, as stated above, this is happening when there aren't enough usages. Not sure why it's giving this error instead of the divide by 0 error. Going to take some bug hunting here.