#000 - Fix authorization for /admin/oauth/token.

1. It was earlier /oauth/token. Now, it is /admin/oauth/token.

2. Earlier, it was lower in the chain of auth definitions. Now, it has to be
   above, because there is a catch-all /admin/** below it (around line 270)
   which will override this, if it is below.

This change allows the OAuth client to get a token to use for further requests.
#000 - Upgrade joda-time.

jruby-1.7.11 includes joda-time 2.3 (see dependencies section
here: http://maven-repository.com/artifact/org.jruby/jruby-core/1.7.11). Go
was using joda-time 1.6. There is an incompatibility in constructors between
these versions, and some oauth code in token.rb#before_create failed, since
it picked up the older joda-time class.
#000 - Fix another oauth_client_id => client_id issue.

In new engine, it is client_id.
#000 - Add clientId related methods.

getClientId() and setClientId() are called through Rails reflection,
from model_base.rb. Earlier, since the column name was oauth_client_id,
it used to call getOAuthClientId() instead.
#000 - Fix authorization for other oauth routes.

Earlier, /oauth/authorize, /oauth/user_tokens and /oauth/user_tokens/revoke/:token_id
were all authorized by ROLE_USER. As with the earlier commit, now that they are all
prefixed by /admin, the catch-all /admin/**=ROLE_SUPERVISOR rule kicks in for them.

But, they should be ROLE_USER as earlier.
Splitting OauthRepository#saveToken and OauthRepository#saveOauthToken. Adding tests for the newly added methods.