Improve build system.

Author: jjrv

package.json

@@ -9,7 +9,7 @@
   "scripts": {
     "tsc": "tsc",
     "rollup": "rollup",
-    "prepublish": "(node src/checkver.js ge 5.0.0 && tsc -m es6 --outdir dist/esm -p src && rollup -c) || tsc -p src",
+    "prepublish": "(checkver ge 5.0.0 && tsc -m es6 --outdir dist/esm -p src && rollup -c) || tsc -p src",
     "test": "tsc -p test && node test/test.js"
   },
   "author": "Juha Järvi",
@@ -27,8 +27,9 @@
     "gmp"
   ],
   "devDependencies": {
-    "@types/node": "^10.12.0",
+    "@types/node": "^10.12.1",
+    "autoroll": "^0.1.0",
     "rollup": "^0.66.6",
-    "typescript": "^3.1.3"
+    "typescript": "^3.1.4"
   }
 }

rollup.config.js

@@ -1,15 +1 @@
-const pkg = require('./package.json');
-
-module.exports = {
-	input: pkg.module,
-	output: [
-		{
-			file: pkg.main,
-			format: 'cjs'
-		}, {
-			file: pkg.browser,
-			name: pkg.name,
-			format: 'umd'
-		}
-	]
-};
+module.exports = require('autoroll')(require('./package.json'));