[#63]Change the cache machanism to make it possible to store cache files
in separated folds under parant work cache fold.
[#63]Put cache of new products content module into work/modules/content
[#63]Put cache files of feature products content module into
work/modules/content fold
[#63]Put cache files of slide images module into work/modules/content
[#63]Put cache files of generating by upcomping products module into 
work/modules/content fold
[#63]Put cache files generated by also purchased module into
work/modules/content fold