Fix:vehicle: parse all gps data then call callbacks|

Fix:vehicle: parse all gps data then call callbacks|
Call after all is parsed, GPGGA is not the last sentence of data.
How heading and speed are for the true last position.
This would lose points for logging, if can not keep with 1 sec
updates ,may be solved with log callback.
If graphics lag, will produce only one update if there are
several fixes in the buffer.

git-svn-id: https://navit.svn.sourceforge.net/svnroot/navit/trunk@1711 ffa7fe5e-494d-0410-b361-a75ebd5db220