Create changelog.txt
Update package.json
Merge branch 'master' into dev

Conflicts:
	changelog.txt
Make it possible for confidential clients to refresh tokens.  Also, update the web sample app to use the current middleware that has been separated from the core express package.
Update doc comment on acquireTokenWithClientCredentials to indicate that the new clientSecret parameter is optional.
Add standard ADAL ID request headers.
Update changelog and version in prep for next release.
The previous version was published with a corrupt package.  Update and republish.
Implement creation of self signed jwt for assertion based auth.
Fix bug in self signed JWT creation.  The header must contain the cert thumbprint.  The jwt-simple lib doesn't provide a way to do that.  Switching to customer implementation.
This should have been part of the last commit, 354704bba47babd3de39583a6d86fc6965a4897a.
Tests were broken by a change in the nock package.  This fixes the issue by trimming the path from any hosts passed to nock.
Get basic cert auth happy path implemented.
Merge branch 'dev' into cert_auth

Conflicts:
	test/util/util.js
Update basic self-signed-jwt test to actually check that the returned jwt matches what was expected given static inputs.
Complete self-sign-jwt validation code and tests.
Add end to end tests for client assertion flow.
Add sample for certificate/client assertion flow.