Adds Copy Header task to the Build Phase to fix the need to create a configuration for OHAttributedLabel when using configurations other than Debug and Release

Instead of having to change the project settings whenever you are archiving or building using a configuration that is not the default Debug or Release, this pull request makes it so you can always archive and build no matter the configuration. The project using OHAttributed label only needs to specify: "$(BUILT_PRODUCTS_DIR)/../../Headers" as a User Header Search path (including quotes).