Create landing page for phenotype terms

[balhoff]

Currently anatomical entities, taxa, and genes can all be traversed to detail pages of their own. Need to create a version for phenotype terms.

[wdahdul]

Jim, is this referring to the phenotype tab, or phenotype popup box?

[balhoff]

I originally envisioned a page per phenotype. But we decided together to morph this into the popup box idea.

[balhoff]

This is now covered by #105 .