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.