Use SimpleDateFormat instead of #inst (flaky)

#inst was failing when run as `lein test`, but not if I ran
`lein test leiningen.test.keys`. Something's screwy with
data-readers.
Add regression test for file.encoding override
Merge branch 'no-inst'
Merge branch 'test-1676-fie-encoding'
Merge remote-tracking branch 'upstream/master'