ecCodes version 2.6.0 released

New tool: codes_split_file. Point to the new confluence tools documentation page.
Example:
% time grib_set -s date=20171201,shortName=t 1million.grib1 reference.grib
219.394u 0.515s 3:40.00 99.9%   0+0k 0+338784io 0pf+0w

% time ./grib_set_parallel_split.sh 1million.grib1 final.grib date=20171201,shortName=t
376.212u 1.675s 0:51.33 736.1%  0+0k 0+1016416io 0pf+0w

Mention ECC-592 => change of some key names (WMO update v29)

Ignore "ECC-588: new Fortran functions for direct access to messages in a file". No tests have been added and also needs proper documentation

Add note to FAQ re finding all namespaces: grib_ls -n XX

Change to output of bufr_dump: localYear, etc keys