Intensity not used in BlendModesOverlay shader's alphablend mode

All the other modes use intensity as a way to fade in/out the screen overlay effect. This can be easily fixed by changing line 82 of the shader from:

return lerp(tex2D(_MainTex, i.uv[1]), toAdd, toAdd.a);

to:

return lerp(tex2D(_MainTex, i.uv[1]), toAdd, toAdd.a * _Intensity);

which would make it behave more in line with the other modes, as well as be more useful.