Development (#152)

* Update login widget section in readme (#133)

* Updates Server endpoints to v4 (#135)

* Changes SDK to use server v4 endpoints. Updates test cases

* 1. Adds version and AZP validation 2. Updates iss validation

* Issue 2439 (#138)

Removed azp check

* update version to 6 (#140)

* Logout wrapper (#144)

* added a wrapper logout function in AppID class which calls AppIDAuthorizationManager's logout

* updated readme with the new AppID's logout wrapper

* added slack link (#147)

* add some description to logout (#149)

* update (#151)