New translations and some fixes

[fmfdias]

Added flags to the translated fields so that the user can easily identify wish fields are locale dependent. (Only added for 'en' and 'pt-PT' locale) Fixed the product duplicate method so that it supports locales like 'pt-PT', 'en-US', etc... Added translations to the following fields:

• Spree::Image
  • alt
• Spree::Property
  • presentation
• Spree::ShippingMethod
  • description
• Spree::TaxCategory
  • name Rake task to copy data from untranslated fields to their specific translations tables. This changes were based on the 1.2 branch and that's why the pull request is made specifically to that branch.

[fmfdias]

Added support for product search in the multiple languages supported by the store. It doesn't search all the translations, just the one that matches the current locale, but it's easy to change that.

[sbounmy]

Sorry for taking such a long time to merge this. Thanks for the great work, I've merged most of this into master : https://github.com/jipiboily/spree_multi_lingual/commit/acf0cdf21b26fa6f36a048c0db90ad75e091673d