Run GLOBK to get 3-epoch (4-yr) velocities

Get velocities from the 4-year span:

$ rm globk_vel.org globk_vel.log
$ globk 6 globk_vel.prt globk_vel.log eura.gdl globk.cmd VEL >& globk.out

where the VEL token at the end tells globk to uncomment the lines in globk.cmd that begin with VEL.

Check the globk_vel.org file under EXPERIMENT LIST for the chi2 increments (< 1.0) in stacking the 3 H-files and the stabilization statistics in the VEL STATISTICS and POS STATISTICS lines. For this network and the IGS14 (ITRF2014) .apr file, the 9 stabilization stations fit the reference frame in velocity at the level of ~ 1 mm/yr horizontal and 5 mm/yr vertical with uncertainties about half of the rms.