Fix persp camera

Sometimes your persp will begin to tumble on it's axis rather than rotate around the focused object. Quick fix is to just delete it and replace it, but you cannot delete it by default because it's set to be a startupCamera. This will change that attribute and replace it with a new one.

string $camera = findStartUpCamera( "persp" );
string $camera2[] = `camera -n persp -hc "viewSet -p %camera"`;
camera -e -sc 0 $camera;
delete "persp";
rename $camera2[0] "persp";
camera -e -sc 1 "persp";