Copy kit javascripts to private namespace in public folder

We want to make sure that any shared JS files we create can't have name
collisions with files the user wants to create. Putting the files in a
separate namespaced folder mitigates against this.

__tests__/spec/build.js

@@ -87,7 +87,7 @@ describe('the build pipeline', () => {
     it('copies javascript to the public folder', () => {
       expect(fs.copyFileSync).toHaveBeenCalledWith(
         path.join(projectDir, 'lib', 'assets', 'javascripts', 'kit.js'),
-        path.join('public', 'javascripts', 'kit.js')
+        path.join('public', '_kit', 'javascripts', 'kit.js')
       )
 
       expect(fs.copyFileSync).toHaveBeenCalledWith(

app/views/includes/scripts.html

@@ -3,9 +3,9 @@
   <script src="{{scriptUrl}}"></script>
 {% endfor %}
 
-<script src="/public/javascripts/kit.js"></script>
+<script src="/public/_kit/javascripts/kit.js"></script>
 <script src="/public/javascripts/application.js"></script>
 
 {% if useAutoStoreData %}
-  <script src="/public/javascripts/auto-store-data.js"></script>
+  <script src="/public/_kit/javascripts/auto-store-data.js"></script>
 {% endif %}

lib/build/tasks.js

@@ -45,7 +45,7 @@ function generateAssetsSync ({ verbose = false } = {}) {
   if (verbose) process.stdout.write('done\n')
 
   if (verbose) process.stdout.write('copying assets...')
-  copyAssets(libAssetsPath, paths.public)
+  copyAssets(libAssetsPath, path.join(paths.public, '_kit'))
   copyAssets(paths.assets, paths.public)
   if (verbose) process.stdout.write('done\n')
 }