Add support for prev/next/self links when returning paginated results. To do this: 1) change "data" envelope from an array to a dict 2) move the "data" array to the "collection" property, which is an array of elements in the collection. 3) add @links dict keyed by link relation: self, next, prev. Each relation is an array of dicts with uri and rel keys. In this case there is only one element, but there is nothing preventing a relation from having multiple url's. So this follows the formatting needed for the general case. Relations are present only if it makes sense. So first page has no prev and last page has no next. 4) add @total_size with number of element selected if they were not paginated. Replicates data in X-Count-Total header. Changed index to start at 1. So the first page is page_index 1 and not page_index 0. (So I am no longer surprised when I set page_index to 1 and am missing a bunch of records 8-)). Also a small fixup, json response ends with a newline so printing the data, or using curl makes sure that anything printing after the json output (like shell prompts) is on a new line. Tests added for all cases.

Debugging Aids
--------------

Try turning on logging of DEBUG level messages. This may be done a number
of ways, depending on what it is you're testing:

1. If you're testing the database unit tests, then set the environment
   variable ``LOGGING_LEVEL=DEBUG``. This may be done like so:

    LOGGING_LEVEL=DEBUG python run_tests.py

   This variable replaces the older HYPERDBDEBUG environment var.

2. If you're testing a particular tracker, then set the logging level in
   your tracker's ``config.ini``.

SENDMAILDEBUG
=============

Set to a filename and roundup will write each email message
that it sends to that file instead to the internet. 
This environment variable is independent of the python -O flag.