Keep minifiers out of built programs

This breaks the path meteor-platform -> webapp -> boilerplate-generator
-> spacebars-compiler -> minifiers which ended up shipping all of uglify
with each built app, even though the code generated in
boilerplate-generator is just eval'd without ever being shown to humans.

Beautification still works on JS generated by templating (*.html),
though.

packages/spacebars-compiler/compiler.js

@@ -90,14 +90,15 @@ SpacebarsCompiler.codeGen = function (parseTree, options) {
 };
 
 SpacebarsCompiler._beautify = function (code) {
-  if (Package.minifiers && Package.minifiers.UglifyJSMinify) {
-    var result = UglifyJSMinify(code,
-                                { fromString: true,
-                                  mangle: false,
-                                  compress: false,
-                                  output: { beautify: true,
-                                            indent_level: 2,
-                                            width: 80 } });
+  if (Package.minifiers) {
+    var result = Package.minifiers.UglifyJSMinify(
+      code,
+      { fromString: true,
+        mangle: false,
+        compress: false,
+        output: { beautify: true,
+                  indent_level: 2,
+                  width: 80 } });
     var output = result.code;
     // Uglify interprets our expression as a statement and may add a semicolon.
     // Strip trailing semicolon.

packages/spacebars-compiler/package.js

@@ -11,7 +11,10 @@ Package.onUse(function (api) {
   api.use('blaze-tools');
 
   api.use('underscore');
-  api.use('minifiers', ['server']);
+  // The templating plugin will pull in minifiers, so that generated code will
+  // be beautified. But it's a weak dependency so that eg boilerplate-generator
+  // doesn't pull in minifiers.
+  api.use('minifiers', ['server'], { weak: true });
   api.addFiles(['templatetag.js',
                  'optimizer.js',
                  'codegen.js',

packages/templating/package.js

@@ -10,7 +10,13 @@ Package.describe({
 
 Package.registerBuildPlugin({
   name: "compileTemplates",
-  use: ['spacebars-compiler'],
+  // minifiers is a weak dependency of spacebars-compiler; adding it here
+  // ensures that the output is minified.  (Having it as a weak dependency means
+  // that we don't ship uglify etc with built apps just because
+  // boilerplate-generator uses spacebars-compiler.)
+  // XXX maybe uglify should be applied by this plugin instead of via magic
+  // weak dependency.
+  use: ['minifiers', 'spacebars-compiler'],
   sources: [
     'plugin/html_scanner.js',
     'plugin/compile-templates.js'