Include all ticket details/journals (comments etc.) in index API response.

By default if you query for a list of tickets

/issues.xml?created_on=%3E%3C2013-02-09%7C2013-02-10&include=journals&li
mit=10"

the response doesn't include comments, changes in assignees etc. This
information would only be included if you query a single ticket at a
time.

This change adds extended information to index call as well.