Resolve the case where a single cell type has multiple characterizing marker sets

[johardi]

A screenshot of a fat cell (http://purl.obolibrary.org/obo/CL_0000136):

In this example, the fat cell has 3 different characterizing marker sets instead of only one. A possible problem is because the cell location is not well defined and lacks of differentiation.

Ideally, a cell type is named based on its particular location and it gets only 1 set of characterizing markers.

• fat cell of subserosa (fat cell in subserosa) has characterizing marker set of "BID"
• fat cell of submucosa of cecum has characterizing marker set of "BID"
• fat cell of myocardium of right atrium has characterizing marker set of "GPAM, FASN, LEP"
• fat cell of atrioventricular node has characterizing marker set of "GPAM, FASN, LEP"
• fat cell of pancreatic fat pad has characterizing marker set of "HOXC8, HOXC9, LEP"

[anitacaron]

Related #16