Removed gl_PerVertex overrides

Fixes #509

data/shaders/deferredshadows/debug.vert

@@ -14,11 +14,6 @@ layout (binding = 0) uniform UBO
 
 layout (location = 0) out vec3 outUV;
 
-out gl_PerVertex
-{
-	vec4 gl_Position;
-};
-
 void main() 
 {
 	outUV = vec3(inUV.st, gl_InstanceIndex);

data/shaders/deferredshadows/deferred.vert

@@ -14,11 +14,6 @@ layout (binding = 0) uniform UBO
 
 layout (location = 0) out vec2 outUV;
 
-out gl_PerVertex
-{
-	vec4 gl_Position;
-};
-
 void main() 
 {
 	outUV = inUV;

data/shaders/deferredshadows/mrt.vert

@@ -23,11 +23,6 @@ layout (location = 2) out vec3 outColor;
 layout (location = 3) out vec3 outWorldPos;
 layout (location = 4) out vec3 outTangent;
 
-out gl_PerVertex
-{
-	vec4 gl_Position;
-};
-
 void main() 
 {
 	vec4 tmpPos = inPos + ubo.instancePos[gl_InstanceIndex];

data/shaders/deferredshadows/shadow.geom

@@ -16,11 +16,6 @@ layout (binding = 0) uniform UBO
 
 layout (location = 0) in int inInstanceIndex[];
 
-out gl_PerVertex
-{
-	vec4 gl_Position;
-};
-
 void main() 
 {
 	vec4 instancedPos = ubo.instancePos[inInstanceIndex[0]]; 

data/shaders/deferredshadows/shadow.vert

@@ -7,11 +7,6 @@ layout (location = 0) in vec4 inPos;
 
 layout (location = 0) out int outInstanceIndex;
 
-out gl_PerVertex 
-{
-	vec4 gl_Position;   
-};
-
 void main()
 {
 	outInstanceIndex = gl_InstanceIndex;