First commit
Edits to README
Switch to Shiny Server open source
Log to files instead of to console
Update README to use log directory
Fix typo in README
Switch to rocker/r-base

The rocker/r-base image uses Debian instead of Ubuntu, so a few additional
changes are needed.
Update README
Quieter wget output
update-local no longer needed
Add r-check Dockerfile
Move code into check_all.R script
Don't re-document package before check
Automatically update R packages before check
Update check_all script
Miscellaneous fixes
Clean up revdep check results
Add workaround for CRAN repo in R-devel
Add devel libraries for mysql and postgres
Install devtools in Rdevel