Add greek to locale.py

I think I got it right.
Merge pull request #10 from otommod/patch-1

Add greek to locale.py
merge of cleg's locale updates into master
re-added otommod's greek locale data
tweaks to locale architecture / api
Updated docs a little bit

As now we use abbreviations for locales — we need to reflect it in docs
Merge pull request #13 from cleg/patch-1

Updated docs a little bit
zh_CN and zh_TW