Merged in hermr2d2/espurna/npm_dependencies (pull request #33)

Make building the web interface easier by automatically installing the dependencies.

Approved-by: Hermann Kraus <hermr2d2+git@gmail.com>
Approved-by: Tomblarom <k.nikulski@gmail.com>
Approved-by: Xose Pérez <xose.perez@gmail.com>

code/build.sh

@@ -28,6 +28,12 @@ echo "Building for version $version"
 # Create output folder
 mkdir -p firmware
 
+if [ ! -e node_modules/gulp/bin/gulp.js ]; then
+    echo "--------------------------------------------------------------"
+    echo "Installing dependencies..."
+    npm install --only=dev
+fi
+
 # Recreate web interface
 echo "--------------------------------------------------------------"
 echo "Building web interface..."