Grunt clean on sbt clean so we don't rely on stale templates
I don't see a way to make a run vs start vs stage decision in SBT on resource directories (because I'm an SBT noob) so here we are doing this in Grunt.
This change in build.sbt is thin, but needs some patch to your yeoman produced grunt file which isn't in this project.  See below

diff --git a/ui/Gruntfile.js b/ui/Gruntfile.js
index a5365af..225ae08 100644
--- a/ui/Gruntfile.js
+++ b/ui/Gruntfile.js
@@ -132,6 +132,12 @@ module.exports = function (grunt) {

     // Empties folders to start fresh
     clean: {
+      twirl: {
+        files: [{
+          dot: true,
+          src:['twirl']
+        }]
+      },
       dist: {
         files: [{
           dot: true,
@@ -333,6 +339,24 @@ module.exports = function (grunt) {

     // Copies remaining files to places other tasks can use
     copy: {
+      'twirl-dev': {
+        files: [{
+           expand: true,
+           dot: true,
+           cwd: '<%= yeoman.app %>',
+           dest: 'twirl',
+           src: ['*.scala.html']
+        }]
+      },
+      'twirl-dist': {
+         files: [{
+           expand: true,
+           dot: true,
+           cwd: '<%= yeoman.dist %>',
+           dest: 'twirl',
+           src: ['*.scala.html']
+         }]
+      },
       dist: {
         files: [{
           expand: true,
@@ -400,7 +424,6 @@ module.exports = function (grunt) {
     grunt.task.run([
       'clean:server',
       'wiredep',
-      'concurrent:server',
       'autoprefixer',
       'watch'
     ]);
@@ -419,7 +442,13 @@ module.exports = function (grunt) {
     'karma'
   ]);

-  grunt.registerTask('build', [
+  grunt.registerTask('build-dev', [
+    'clean:twirl',
+    'copy:twirl-dev'
+  ]);
+
+  grunt.registerTask('build-dist', [
+    'clean:twirl',
     'clean:dist',
     'wiredep',
     'useminPrepare',
@@ -432,12 +461,13 @@ module.exports = function (grunt) {
     'cssmin',
     'uglify',
     'filerev',
-    'usemin'
+    'usemin',
+    'copy:twirl-dist'
   ]);

   grunt.registerTask('default', [
     'newer:jshint',
 //    'test',
-    'build'
+    'build-dev'
   ]);
 };
Merge branch 'feature/reliable-templates' of https://github.com/centraldesktop/play-yeoman into develop

Conflicts:
	play-yeoman/project/plugins.sbt
	sbt-yeoman/app/com/tuplejump/sbt/yeoman/Yeoman.scala