The ornamental design for a projector, as shown and described.
FIG. 1 is a perspective view of a projector showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof wherein the broken lines showing portions of the projector are included for the purpose of illustrating environmental structure and form no part of the claimed design;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom view thereof wherein the broken lines showing portions of the projector are included for the purpose of illustrating environmental structure and form no part of the claimed design.