Instead, add env var for overriding user input

.travis.yml

@@ -8,8 +8,6 @@ addons:
       - g++-4.8
 env:
   - CXX="g++-4.8"
-before_script:
-  - npm run build-server
 node_js:
   - "7"
   - "6"

postinstall.sh

@@ -1,5 +1,11 @@
 #!/bin/sh
 
+if test "$BUILD_OVERRIDE" = "Y"; then
+    echo "Running $npm_package_scripts_build_server"
+    $npm_package_scripts_build_server
+    exit $?
+fi
+
 echo "In order to run the server, the source files in src/ must be transpiled to lib/.  This will overwrite any changes you have made to the files in lib/."
 echo -n "Do you want to build now? [y/N]? "
 read answer