qtscript: Call the right event on transporter exit.

It used to be known as CALL_START_NEXT_LEVEL in wzscript,
but in fact this is the event of the transporter flying
far enough from the LZ to trigger the start
of the offworld mission.

It does not seem to cause ambiguity with the event
of the transporter actually crossing the map boundary
(eg., after landing on the away mission).
jscam: Convert cam1-2s.{vlo,slo} into cam1-2s.js.

In the process:
- add a new sort of victory conditions for the pre-away mission.
- fix defeat on mission timeout (aint automatic).
- start fixing loading rules.js for the converted levels.
- fix the POTFILES.in file, adding campaign scripts here.
- add a new function: camSetupTransporter.
- fix crash when "let me win" is called and some
  in-object artifacts were already picked up

refs ticket:4234