release fixes

Author: akshay-99

.gitignore

@@ -18,4 +18,5 @@ p5-website/
 coverage/
 lib/p5-test.js
 release/
+parameterData.json
 yarn.lock

Gruntfile.js

@@ -561,5 +561,9 @@ module.exports = grunt => {
     'watch:yui'
   ]);
   grunt.registerTask('yui:build', ['yui']);
+
+  // builds the docs and the library before release
+  grunt.registerTask('prerelease', ['yui', 'build']);
+
   grunt.registerTask('default', ['lint-no-fix', 'test']);
 };