Invalid HTML generated for lists with empty bullets

[bcspragu]

I've come across a weird edge case that results in bad HTML (e.g. a bunch of extra < and > tags), and written up the failing test in Silicon-Ally#1

I tried running the test with dlv test, but wasn't able to figure out where things go off the rails. I noticed at one point early on, fm.Val becomes <ol>, e.g. it already has the wrapping tags, but I couldn't figure out why that happens only for lists with a single non-blank bullet. See testdata/list5.json for a passing example.

BTW, thanks for making this library!