The ornamental design for a projector, as shown and described.
FIG. 1 is a perspective view of a projector;
FIG. 2 is a front view of the projector of FIG. 1;
FIG. 3 is a rear view of the projector of FIG. 1;
FIG. 4 is a left-side view of the projector of FIG. 1;
FIG. 5 is a right-side view of the projector of FIG. 1;
FIG. 6 is a top plan view of the projector of FIG. 1; and,
FIG. 7 is a bottom plan view of the projector of FIG. 1.
The broken line showing portions of a projector in FIGS. 3, 4, and 7 is included for the purpose of illustrating environmental structure and forms no part of the claimed design.