mergeCells needs to call cells with p=1 for deleted cell types

[patrickjdanaher]

Problem: If a cell has p=1 for a deleted cluster, you can't calculate its logliks.

Solution:

• run probs2loglik
• delete columns for to_delete cell types
• Identify cells with only -Inf values in logliks
• Run Mstep on those rows

[patrickjdanaher]

Alternative approach: insitutype outputs logliks matrix and a vector of probs.

What would be needed:

• [x] insitutype outputs logliks and prob vector
• [x] runinsitutype outputs logliks
• [x] flightpath_layout can take probs OR logliks
• [x] lightpath_plot can take probs OR logliks
• [x] flightpath_plot must extract logliks from insitutype_result, not probs
• [x] update all the above docs
• [x] up[date unit test expectations - logliks not probs