Add layer overpass.

assets/leaflet-layer-overpass/gulpfile.js

@@ -0,0 +1,14 @@
+var gulp = require('gulp');
+var concat = require('gulp-concat');
+var uglify = require('gulp-uglify');
+var rename = require('gulp-rename');
+
+gulp.task('default', function() {
+  return gulp.src('./src/*.js')
+    .pipe(concat('OverPassLayer.js'))
+    .pipe(gulp.dest('./dist/'))
+    .pipe(uglify())
+    .pipe(rename({ extname: '.min.js' }))
+    .pipe(gulp.dest('./dist/'));
+});
+