update "+" label in priors panel to "+ Add Prior". fixes #20
update "+" label in priors panel to "+ Add Prior". fixes #20

CompEvol/beast2,CompEvol/beast2,Anaphory/beast2,tgvaughan/beast2,Anaphory/beast2,Anaphory/beast2,CompEvol/beast2,CompEvol/beast2,tgvaughan/beast2,Anaphory/beast2,tgvaughan/beast2,tgvaughan/beast2