build: Exclude svelte from Rollup’s external module list (#767)

Fixes #766

Author: delucis

rollup.config.js

@@ -17,8 +17,9 @@ import pkg from './package.json';
 import typescript from 'rollup-plugin-typescript2';
 const subpackages = require('./subpackages');
 
+const internalDeps = ['svelte'];
 const external = [
-  ...Object.keys(pkg.dependencies),
+  ...Object.keys(pkg.dependencies).filter(name => !internalDeps.includes(name)),
   'react',
   'socket.io-client',
 ];