replace current logger with clay-log

[amycheng]

use Clay-log instead of the logger that is being used now.

we might as well be consistent with the other clay things.

see here for usage

[nelsonpecora]

Note: we'll also want to standardize what the output looks like (e.g. what happens on errors, what do successes look like) since we're making heavy use of stdin / stdout

[nelsonpecora]

Actually, it looks like we can't use clay-log, since that hardcodes its output to stdout

[nelsonpecora]

should work with clay/clay-log#5