Unisubs GH-915 - Updating ISO_639_1 mappings

This patch comes to update the ISO_639_3 mappings to ISO_639_1 where applicable. These changes were based on the list provided by @jzurawell.

The only mappings that were not touched are:

ISO 639_1 'no' is already mapped as ISO 639_1 "nn" -> Norwegian Nynorsk. I understand that 'no' is the macrolanguage and 'nn' is a dialect. We should open a separate issue for this one to separate and create new mappings.


'Fry' => 'Fy', as it's currenty mapped to fy-nl' ('Frisian'), 'Frysk'). A separate issue for handling this one would be good.

Visually, the crossed ones were changed.

![5db4c74a-2b85-11e3-9ba8-4628f16ff3a7](https://f.cloud.github.com/assets/1544280/1345574/c6af77ba-3691-11e3-9e9e-752ada08f3d7.png)