Checks that a callback passed to Promise.prototype.nodeify is callable before attempting to call

Signed-off-by: Christopher Rogers <chrissrogers@gmail.com>
Simplifies nodeify callable check
Merge pull request #36 from chrissrogers/prototype-nodeify-callable-safety

Promise.prototype.nodeify callback safety
Deprecate from, cast and multi-arg all
"catch" is a reserved word in ES3
Merge pull request #41 from ljharb/fix_es3

"catch" is a reserved word in ES3
Merge branch 'deprecations'

Conflicts:
	index.js
	test/extensions-tests.js
Release 5.0.0
Allows an inheriting constructor to return itself when calling .then

Signed-off-by: Christopher Rogers <chrissrogers@gmail.com>