make group failure warning optional (but enabled by default)
log exit events from within session rather than process manager
add preference to control update checking
don't log from program options report warning method
don't log errors after call to ignoreSignal in server main
Merge pull request #56 from rstudio/feature/environment-grid-view

Add grid view for environment pane
fix exception when listing environment during non-top-level but non-debug sessions