Adds individual graphs for likelihoods and AICc for whenever the problems with the models get fixed.
Returns a blank for the Poisson lognormal likelihood if the likelihood value is less than zero or -inf.
Adds note about failed model/site combinations to data section.
Adds note about calculation of AICc weights when not all models fit to the data.
Brainstorming discussion.
Merge remote-tracking branch 'upstream/master'
Merge pull request #25 from embaldridge/master

Merging some chapter 1 additions plus a work around for the problem with the logseries.