Made changes to the AUTHENTICATE AN ACCOUNT section under ACCOUNTS resou...

...rce

+ Added a simple POST example of a successful request
+ Added explaination the value field being passed
+ Added clarification that authentication is done on the application resource

+ Modified the text for the link to more information regarding authentication under the APPLICATIONS resource
+ Modified titles in Java and Ruby from 'Authenticate Accounts' to 'Authenticate an Account'
+ Modified section in Java and Ruby to match REST docs

+ Deleted the note refering to workflows only being able to be modified by administrators
+ Deleted the Authenticate an Account section from the DIRECTORY resource section.  Authentication is not handled by the directory resource