Add a script to build merged docs

build_docs.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+set -e
+
+mkdir doc
+
+for crate in $(echo phf_shared phf_macros phf phf_codegen phf_generator); do
+    rm -r $crate/target
+    mkdir -p $crate/target
+    (cd $crate/target && ln -s ../../doc)
+    (cd $crate && cargo doc --no-deps)
+done