ISSUE-97 Consolidate product listing pages into one shared code base

mitigate against empty result sets
Need proper test for displaying filter selects
fixing queries for some listing boxes
Fix random order by
Fix display of price etc
ensure array is initialized
fix for when  category is invalid
fix upcoming box display order
CHANGE-89 - Fix typos
CHANGE-564B - Relocate version constants to the beginning of the autoloader process.
ISSUE-98 Admin Action Classes

set a better PHP_SELF
fix poor link building
Merge pull request #61 from zencart/v160

zc 160