Force TechRacer maps when image map is selected. Fixes Google Code issue #882
If you start a TechRacer map with an image map selected, the resulting map will likely to be completely unplayable.
So this commit disables this.
Fuzzy BeardBoth WaysLeft Rite OutI. P. FreleyAl. KaholicEye-patch JimHaunter BowenLong-nose KiddStubborn DiegoToothless WayneRoger KarrghRusted PeterYumee SilverHawkin HaunterCruise SeymourRusted DiegoFirstRusted HaunterPeter BuckettYumee GunpowderCrowe JimIron DiegoOne-eyed AyeeDiego R. FlintMorrisAyee MorganJim MorganCrook R. EdvardDiego DoverMike the pirateSilverIron LukeDirty BenYumee CallesWayne BowenTimmy the pirateRackham BloodAl. KaholicEye-patch ShokRusted T. BenDirty O'JohnCutlass Cain