update error option titles; remove ErrorManager dependency on UIPrefs
Merge pull request #46 from rstudio/feature/error-management

Merge pull request #46 from rstudio/feature/error-management
move error management prefs above encoding pref
allow other variations of bin/rsession
Merge remote-tracking branch 'origin/master' into feature/environment-improvements
improve environment pane handling of large objects, long vectors, and pathological cases