adding 'full_name' for all currencies

Based on this PR: https://github.com/hexorx/currencies/pull/9

Added 'full_name' for all currencies, to allow for displaying the full name as listed in the ISO spec. Should just allow for the full_name attribute to be called from the Currency object. Let me know if you need me to add any additional tests or anything? Don't know if they're needed or not since the full name would be an inefficient way to look up anything?

(also as a heads up, one of my addons nuked all the whitespace, so sorry about all the extra ``+`` ``-`` lines.