tweaks to marshaling to/from X509Certificate

git-svn-id: https://svn.forgerock.org/openam/branches/sts_x509@10245 0f4defcf-c51a-4c67-9f44-6fb5eba73c5d
changes to RestAuthX509CallbackHandler and related sts functionality to parse json callback

git-svn-id: https://svn.forgerock.org/openam/branches/sts_x509@10248 0f4defcf-c51a-4c67-9f44-6fb5eba73c5d
adding a X509TokenState class to represent the input token type in a rest-sts token transformation invocation.

git-svn-id: https://svn.forgerock.org/openam/branches/sts_x509@10250 0f4defcf-c51a-4c67-9f44-6fb5eba73c5d