1. A vision system for a vehicle, said vision system comprising: a single forward facing camera disposed at a vehicle equipped with said vision system; said camera comprising a CMOS imaging sensor and a lens; said imaging sensor comprising a plurality of photo-sensing pixels arranged in a matrix of multiple horizontal rows of photo-sensing pixels and multiple vertical rows of photo-sensing pixels; wherein said camera has a field of view exteriorly of the equipped vehicle; wherein said imaging sensor is operable to capture image data representative of a scene exterior of the equipped vehicle and in the exterior field of view of said camera; a control comprising a processor; wherein said camera and said processor are disposed in a unitary module installed in the equipped vehicle; wherein said processor, responsive to processing of captured image data, detects headlights of oncoming vehicles within the exterior field of view of said camera when the equipped vehicle is operated under nighttime conditions, and wherein said control, responsive to said headlight detection, provides an output for a headlamp control system of the equipped vehicle that controls at least one headlamp of the equipped vehicle; wherein said processor, responsive to processing of captured image data, detects lane marks within the exterior field of view of said camera on a road being traveled by the equipped vehicle, and wherein said control, responsive to said lane mark detection, provides an output for a lane departure warning system of the equipped vehicle; wherein said processor processes captured image data via an edge detection algorithm to detect edges of objects present exteriorly of the equipped vehicle and within the exterior field of view of said camera; wherein said processor processes captured image data to estimate distance from the equipped vehicle to a vehicle present exteriorly of the equipped vehicle and within the exterior field of view of said camera; and wherein said unitary module is supplied by an automotive supplier to the manufacturer of the equipped vehicle with software included that is operable by said processor for a plurality of driver assistance systems of the equipped vehicle, said plurality of driver assistance systems including said lane departure warning system of the equipped vehicle and at least one other driver assistance system of the equipped vehicle and wherein said at least one other driver assistance system of the equipped vehicle is selected from the group consisting of (i) said headlamp control system of the equipped vehicle, (ii) a traffic sign recognition system of the equipped system, (iii) a stop light recognition system of the equipped vehicle, (iv) a passive steering system of the equipped vehicle, (v) an object detection system of the equipped vehicle and (vi) an adaptive speed control system of the equipped vehicle.