Added default value for config_image_location

There was no default value for config_image_location.
image_location_width and image_location_height are required fields in
store settings (store_form.tpl)
Fixed incorrect default path to logo.png and cart.png
Revert "Added default value for config_image_location"

This reverts commit 6b2bf6d2155ad199600b94c6db7870cc95a26688.
Added default value for config_image_location
Merge pull request #1606 from tjomamokrenko/master

Some fixes in default config values