Xcode project reorganized to handle localization files
SHELF_NAVIGATION_TITLE value rewritten in a more neutral way
"item" replaced by "issue" to be consistent with the value of DOWNLOAD_FAILED_MESSAGE
Revert "SHELF_NAVIGATION_TITLE value rewritten in a more neutral way"

This reverts commit b4db1238a4b42513f2fa43235337b37eed0a5dcf.