Fix assignment of walk_slack, add default case to switch for unknown option.
Make 180.0 an explicit float.
Cast the return value of abs to an uint32_t
Initialise prev_st with NULL and explicitly check for it.

Opposed to an implicit check by a stop_index greater than 0.
Rewrite tdata_route_new a bit so we don't use mixed initialisation.
While we don't use the stubs. We shouldn't return the latlon value
opposed to a bool.
Explicitly cast the return value of SEC_TO_RTIME to (rtime_t)
Change the floating point division by 60 seconds, to 60.0f opposed to
the default double float.
Make sure the types we are using match the lvalues.

Some minor changes so the number of rounds are always limited to uint8_t.
Match return types, remove random initialisation.