Feature: Add Greek language fulltext search

Last November snowball added support for Greek language [1]. Following the instructions [2], I wrote a patch that adds fulltext search for Greek in Postgres. The patch is attached. 

I would appreciate any feedback that will help in getting this merged.

with kind regards,

Panos

[1] https://github.com/snowballstem/snowball/commits/master/algorithms/greek.sbl

[2] https://github.com/postgres/postgres/blob/97c39498e5ca9208d3de5a443a2282923619bf91/src/backend/snowball/README