move shaders to .glsl files and stringify to .h file.

add crude screenshot facility (using F1 key), it can also be used for debugging
start with shadows using shadowmap, not working yet
add experimental 'ignore' body index in raycast, using b3HitInfo.m_m_hitResult2

btgui/OpenGLWindow/Shaders/useShadowMapInstancingPS.glsl

@@ -0,0 +1,40 @@
+#version 330 core
+//precision highp float;
+
+in Fragment
+{
+     vec4 color;
+} fragment;
+
+in Vert
+{
+	vec2 texcoord;
+} vert;
+
+uniform sampler2D Diffuse;
+uniform sampler2DShadow shadowMap;
+
+in vec3 lightDir,normal,ambient;
+in vec4 ShadowCoord;
+
+out vec4 color;
+
+
+
+void main(void)
+{
+    vec4 texel = fragment.color*texture(Diffuse,vert.texcoord);//fragment.color;
+	vec3 ct,cf;
+	float intensity,at,af;
+	intensity = max(dot(lightDir,normalize(normal)),0);
+	cf = intensity*vec3(1.0,1.0,1.0)+ambient;
+	af = 1.0;
+		
+	ct = texel.rgb;
+	at = texel.a;
+		
+	float bias = 0.005f;
+	float visibility = texture(shadowMap, vec3(ShadowCoord.xy,(ShadowCoord.z-bias)/ShadowCoord.w));
+	
+	color  = vec4(ct * cf * visibility, at * af);	
+}