stdout/stderr around
A lot of functions in the cmd and ctl packages were passing these
around and barely using them. Replaced them with a logger for most
functions. Some functions get an io.Writer instead so that their
tests can find the output they're looking for.
More cleanup on fb-1766: reworked the tests that were using io.Pipe
or os.Pipe to check their results so they now use a bytes.Buffer.
Unexported some variables that didn't need to be exported.
Fixed NewConfigCommand to use the provided stderr, not os.Stderr.
Added tests for rbf_dump, rbf_page, and keygen, since those weren't
being tested at all.
Added chksum_test, final cleanup.
(cherry picked from commit f627199acb)
Renames `config` to `generate-config` and implements a new `config`
command that generates the configuration file based on the current
state instead of printing a static string.
A configurable limit has been added to restrict the number of
mutating calls in a `pql.Query`. This is to prevents requests from
timing out from large queries.
The default is set to 5000 writes per request and is configurable
through the configuration file and the command line flags.
