Fixed a bunch of compile/linking bugs for OS X

BUGS: 339222
only update elevation data if needed

* fixes high CPU load even if float item isn't visible
Fix compile-time errors in elevationprofilefloatitem
fix compilation under Maemo5
add default constructor test
fix usage of Quaternion::slerp()
[API change] take into account that routes can last longer than one day
take number of days into account

* this had been the correct fix in commit 27639676cd021b0d821c0c5d54ff7dd42e107986
debug++
parseTime
wip
realistic route simulation