Merge PR 'sv_gameplayfix_stepmultipletimes 1: Prevent players moving too far/fast...

Merge PR 'sv_gameplayfix_stepmultipletimes 1: Prevent players moving too far/fast when stepping up a staircase'

After the player made some horizontal progress, and before stepping up, it's necessary to recalculate the remaining time and distance for the move. Previously the step up made the player travel (up to) nearly the move's full distance, again.

https://github.com/DarkPlacesEngine/darkplaces/pull/10

branch: bones_was_here/stepup_distance
commits: 365e221966b15c24c6e2f4cbb6e619b0db443ebf

Signed-off-by: bones_was_here <bones_was_here@xa.org.au>