a fix to readRDS that unaccountably works; error logging
log performance of tree updates
temporary workaround for #303

this should avoid the problem of connections somehow getting
used up by readRDS until we find what is really wrong here
Merge branch 'develop' into feature/fix-rcs-ff
Merge branch 'feature/fix-rcs-ff' into develop
Merge branch 'develop' of https://github.com/att/rcloud into develop
delay creation of dom elements in notebook tree

toward #306