Add CI script for finding dead symlinks

.travis.yml

@@ -23,6 +23,7 @@ addons:
 
 script:
   - |
+    bash ./scripts/find-dead-symlinks || exit 1
     bash ./scripts/license-headers-updated || exit 1
     cargo build --all --all-features -j 1 || exit 1
     cargo test  --all --all-features -j 1 || exit 1

scripts/find-dead-symlinks

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+[[ 0 == "$(find . -xtype l | wc -l)" ]] || {
+    echo >2 "DEAD SYMLINKS FOUND"
+    exit 1
+}
+