Added authorization operations

Added authorization operations and ability to get connection by authorization token.
I agree, I'll work on the get and list this weekend!

> My concern here is what happens if the token is given but it's outdated? I did not test it but I think that we run into an exception (404?). 

That token should always be the one used to create the connection.
The getAuthorization() either creates a new authorization, returns an authorization that has already been created, or defaults it to the one used when creating the connection (we actually don't have a get with a token or id yet).

It is so if I have
```
IOpenShiftConnection connection = new OpenShiftConnectionFactory().getConnecton(OpenShiftUtils.CLIENT_NAME, myToken);
```
then
```
connection.getUser().getAuthorization()
```
is the authorization that corresponds to myToken.

And when you authenticate via a token you will only have access to that token's authorization anyways.

so you wouldn't be able to list or get any other authorization.

curl -k  https://openshift.redhat.com/broker/rest/user/authorizations -H "Authorization: Bearer 9e01b053026036a40f14b22f53a2e86447703533cd1b86db9d2e8546b519e7da"

messages":[{"exit_code":1,"field":null,"index":null,"severity":"error","text":"This action is not allowed with your current authorization."}],"status":"forbidden"



and that is b/c you wouldn't want an authorization with read access to use the api's to obtain an authorization with write access.


so the new methods for getting and listing authorizations
```
public Collection getAuthorizations();
public IAuthorization getAuthorization(String id);
```
should only return something when you call them with a connection that is created with a username and password


I wouldn't be opposed to dropping the creation behind the scenes though and if it returns null, you can do a createAuthorization.

so change it to something like this
```
public IAuthorization getAuthorization() throws OpenShiftException {
	if (token != null) {
		this.authorization = new AuthorizationResource(this, new ShowAuthorizationRequest().execute(token));
	}
	return this.authorization;
}
```
It would probability be more straight forward that way anyway.