Project JEDI Tools

- add the session ID only when it's not empty;
- post empty values are not successfully passed to the server, add a dummy value;
- add the indirect back link handling.

Some new demos for the MediaWiki API wrapper:
- list all categories;
- list page back links;
- list page categories;
- list page external links;
- list page wiki links;
- list page templates;
- query page information;
- list user options;
- list user changeable groups;
- list user rate limits.