sync opam with mirage-dev
Use latest Cohttp 0.12.0 API for Auth
Modernize Travis scripts to OPAM 1.2.0 workflow
Turn js_of_ocaml to be off by default and sync OASIS
make js_of_ocaml optional in opam
Remove OCaml 4.00.1 from the test matrix, as Cohttp 0.12.0+ requires 4.01.0+
Fix OCaml version in Travis
explicitly check for cohttp >= 0.12.0

fixes #37
Mark `published_at` and `created_at` fields in Releases to be optional

They may not be set in the case of draft tags.
Bump to 0.9.1
Better log error messages
Merge pull request #39 from dsheets/log-errors

Better log error messages
Tweak Makefile to build JavaScript version by default if `js_of_ocaml` is installed.
release 0.9.2
record PR number in CHANGES
bump to 0.9.2