ropensci/targets: CRAN hotfix and app improvements

Bug fixes tar_test() now skips all tests on Solaris in order to fix the problems shown on the CRAN check page. Enable allow and exclude to work on imports in tar_visnetwork() and tar_glimpse(). Put visNetwork legends on right to deal with how legend nodes always align right within the legend space. Performance Call force() on subpipeline objects to eliminate high-memory promises in target objects. Allows targets to be deployed to workers much faster when retreival is "main" (#279). New features Add a new box to the tar_watch() app to tabulate progress on dynamic branches (#273, @mattwarkentin). Store type, parent, and branches in progress data for tar_watch() (#273, @mattwarkentin). Add a fields argument in tar_progress() and default to "progress" for back compatibility (#273, @mattwarkentin). Add a new tar_progress_branches() function to tabulate branch progress (#273, @mattwarkentin). Add new "refresh" switch to tar_watch() to toggle automatic refreshing and force a refresh. Enhancements Exclude .Random.seed by default in tar_visnetwork(). Spelling: "cancelled" changed to "canceled". Enhance controls and use of space in the tar_watch() app. Centralize internal path management utilities. Configuration Skip clustermq tests on Solaris