Support NetCDF4 compression.

Only available for non-parallel output so either if only one server is used or if the multiple file mode is enabled).

git-svn-id: http://forge.ipsl.jussieu.fr/ioserver/svn/XIOS/branchs/xios-1.0@606 d613d254-d18a-4304-b296-5125d4c4d670