The ornamental design for a projector, as shown and described.
FIG. 1 is a top perspective view of a projector of the present invention;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line showing of projector is included for the purpose of illustrating environment and forms no part of the claimed design. Additionally, the unevenly broken lines in the drawings define the limits of the claimed design.