Sync up generated java code (only comments changed)

Change-Id: I5e9b670eba783b1b158775e9d87d17becd180c5e
Add extra optional auth data fields

Change-Id: I09471773c436f36ed1b673462530b7810571e5c4
Add protocol diagram

Change-Id: I61e31e425b8345bc1f56b0c125b761b5b4e77553
Updated protobufs for new authentication modules in client

Changed Authentication to contain a required string username and a list of AuthenticationEntry protobufs
Added AuthenticationEntry, contains a required string key and a required byte[] value
Also updated .gitignore to ignore IDEA project files

Change-Id: I9cb4a272c9e29f6fd156c0be8744df6770381d34