The ornamental design for a projector, as shown and described.
FIG. 1 is a perspective view of a projector showing my new design;
FIG. 2 is another perspective view seen from the bottom side thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines are for illustrating unclaimed portions of the projector or environmental structures, the broken lines form no part of the claimed design.