add console.error capabilities to log
jshinting
Merge branch 'dev' of https://github.com/ractivejs/ractive into gh-1425
begin guarding other callback invocations from promise returns
Merge branch 'dev' of https://github.com/ractivejs/ractive into gh-1425
warn to use promises instead of callbacks
remove extraneous line
Merge pull request #1426 from ractivejs/gh-1425

oncomplete promise failures are errored to console