Fix broken display of single OTU mapping result.
Fix broken display of single OTU mapping result.

N.B. I'm replaying this commit (f7a762a5c6096faaa99da1fb849403bf6ba419ae)
onto master, to make a proper pull request.

Use the more standard `A` (vs. `STRONG`) element for a single OTU
mapping result. This gives us the correct color from Bootstrap's CSS,
which expects any matching element to have an `href` attribute.
Fixes #619.

OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree