Remove bin/build-favicons (not needed anymore)

bin/build-favicons

@@ -1,16 +0,0 @@
-#!/bin/sh
-sizes="16x16 32x32 48x48 64x64 128x128 256x256"
-for size in ${sizes}; do
-    convert src/favicon.svg \
-        -resize ${size} \
-        -background none \
-        -fuzz 8% \
-        -mattecolor "#FFFFFF" \
-        -alpha set \
-        -channel RGBA \
-        -fill none \
-        -opaque white \
-        -gravity center \
-        -extent ${size} \
-        png32:src/favicon-${size}.png
-done