Update travel-grant.md
Update travel-grant.md

AP MB and AMB: add more explanation on calendar criteria in travel grant explanations.
neicnordic/experimental.neic.nordforsk.org,neicnordic/neic.no,neicnordic/experimental.neic.nordforsk.org,neicnordic/experimental.neic.nordforsk.org,neicnordic/neic.no,neicnordic/neic.no