Clean up redundant and orphaned constants for TEXT_CLOSE_WINDOW
ref: http://www.zen-cart.com/showthread.php?212344-TEXT_CLOSE_WINDOW-in-info_shopping_cart-php-of-No-Effect
Fixes #78 - Remove Attributes Preview Incomplete
Merge pull request #83 from drbyte/v160

Clean up redundant and orphaned constants for TEXT_CLOSE_WINDOW
Merge pull request #84 from drbyte/attr-preview-cleanup

Fixes #78 - Remove Attributes Preview Incomplete
Fixed #87 Incorrect results on download check Admin
Fix #89 Required Text accepting spaces
Merge pull request #86 from ajeh/v160

Fixes #85 shipping quotes that need value of shipping
Merge pull request #88 from ajeh/admin-download

Fixed #87 Incorrect results on download check Admin
Merge pull request #90 from ajeh/trim-required-text

Fix #89 Required Text accepting spaces