patch from Aleksander ‘A.L.E.C' Machniak.

Changes:

1. It's now possible to return analysis as html table (set $HTML_OUTPUT to 1)
2. It's now easier to change sorting of generated analysis (set $SORT_ORDER)
3. In html output, all numbers are formatted to %.2f.

Some edits by me, mostly indentation.

SVN repo at: http://svn.depesz.com/svn/pgsql-tools/trunk