Add "exclusive use to pickup" option.

Make "pickup through melee" optional (disabled by default).
Increased leniency of use to pickup (nice for items with small hitboxes).

shaders/pp/Barrier.fp

@@ -1,3 +1,5 @@
+// barrier shimmering warp overlay
+
 void main()
 {
 	vec2 uv = TexCoord;

shaders/pp/Ghostscreen.fp

@@ -1,3 +1,5 @@
+// ghost artifact refraction bubble
+
 void main()
 {
 	vec2 uv = TexCoord;

shaders/pp/Glitch.fp

@@ -1,3 +1,5 @@
+// glitched screen shader
+
 const float thr1 = 6.4;
 const float thr2 = 8.6;
 const float thr3 = 19.3;

shaders/pp/Invinciscreen.fp

@@ -1,3 +1,5 @@
+// invinciball radial sharpening
+
 vec3 sharpened( vec2 uv )
 {
 	vec3 col = texture(InputTexture,uv).rgb*9.;

shaders/pp/LavaWarp.fp

@@ -1,3 +1,6 @@
+// underwater overlay adapted from original Hexmas sanity effect shader
+// lava version
+
 vec2 calcdist( vec2 duv )
 {
 	vec2 uv = vec2(0.);

shaders/pp/Ragescreen.fp

@@ -1,3 +1,5 @@
+// RAGE
+
 #define TWOPI 6.28318530718
 
 void main()

shaders/pp/RagescreenAlt.fp

@@ -1,3 +1,5 @@
+// less eye-searing rage
+
 #define TWOPI 6.28318530718
 
 void main()

shaders/pp/SilverScope.fp

@@ -1,3 +1,5 @@
+// simple scope overlay + bokeh blur
+
 #define PI 3.14159265
 
 void main()

shaders/pp/SlimeWarp.fp

@@ -1,3 +1,6 @@
+// underwater overlay adapted from original Hexmas sanity effect shader
+// slime version
+
 vec2 calcdist( vec2 duv )
 {
 	vec2 uv = vec2(0.);

shaders/pp/WaterWarp.fp

@@ -1,3 +1,6 @@
+// underwater overlay adapted from original Hexmas sanity effect shader
+// water version
+
 vec2 calcdist( vec2 duv )
 {
 	vec2 uv = vec2(0.);

shaders/pp/ZoomBlur.fp

@@ -1,3 +1,5 @@
+// zoom blur effect adapted from abort_m berserk pulse
+
 void main()
 {
 	vec2 p = CenterSpot-TexCoord;