The ornamental design for a projector, as shown and described.
FIG. 1 is a bottom perspective view of a projector;
FIG. 2 is a top perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left-side view thereof;
FIG. 6 is a right-side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The broken line immediately adjacent to the shaded areas represent the bounds of the claimed design while all other broken lines are included for the purpose of illustrating environmental structure only; the broken lines form no part of the claimed design.