Add libs, libs2min, void and remove flows

`libs`:
Concatinates only. Useful for vendor files if you want them
separately and are using minified versions in developement(why?).

`libs2min`:
Concatenates only BUT transforms the source filename before like so:
path/filename.js -> path/filename.min.js
Useful if you use long versions in dev environment but want to use
minified versions of vendor files in production, have those files
around(bower!) and don't want to mess around minifying them yourself.

`void`:
Does nothing but replaces the block with new reference. Useful if you
have the same block on multiple html files but don't want to concat or
uglify it several times.

`remove`:
Does nothing but removes the block all together. Nothing is left even
not the reference.

Try them out.

lib/config/libs.js

@@ -0,0 +1,25 @@
+'use strict';
+var path = require('path');
+
+exports.name = 'concat';
+
+//
+// Output a config for the furnished block
+// The context variable is used both to take the files to be treated
+// (inFiles) and to output the one(s) created (outFiles).
+// It aslo conveys whether or not the current process is the last of the pipe
+//
+exports.createConfig = function(context, block) {
+  var cfg = {files: []};
+  // FIXME: check context has all the needed info
+  var outfile = path.join(context.outDir, block.dest);
+
+  // Depending whether or not we're the last of the step we're not going to output the same thing
+  var files = {};
+  files.dest = outfile;
+  files.src = [];
+  context.inFiles.forEach(function(f) { files.src.push(path.join(context.inDir, f));} );
+  cfg.files.push(files);
+  context.outFiles = [block.dest];
+  return cfg;
+};

lib/config/libs2min.js

@@ -0,0 +1,25 @@
+'use strict';
+var path = require('path');
+
+exports.name = 'concat';
+
+//
+// Output a config for the furnished block
+// The context variable is used both to take the files to be treated
+// (inFiles) and to output the one(s) created (outFiles).
+// It aslo conveys whether or not the current process is the last of the pipe
+//
+exports.createConfig = function(context, block) {
+  var cfg = {files: []};
+  // FIXME: check context has all the needed info
+  var outfile = path.join(context.outDir, block.dest);
+
+  // Depending whether or not we're the last of the step we're not going to output the same thing
+  var files = {};
+  files.dest = outfile;
+  files.src = [];
+  context.inFiles.forEach(function(f) { files.src.push(path.join(context.inDir, f.replace(/\.js$/, '.min.js')));} );
+  cfg.files.push(files);
+  context.outFiles = [block.dest];
+  return cfg;
+};

lib/fileprocessor.js

@@ -96,8 +96,10 @@ FileProcessor.prototype.replaceWith = function replaceWith(block) {
       result = '<link rel="stylesheet" href="' + dest + '"' + media + '/>';
     } else if (block.defer) {
       result = '<script defer src="' + dest + '"><\/script>';
-    } else if (~['js', 'libs'].indexOf(block.type)) {
+    } else if (~['js', 'libs', 'libs2min', 'void'].indexOf(block.type)) {
       result = '<script src="' + dest + '"><\/script>';
+    } else {
+      result = '';
     }
   }
   return block.indent + conditionalStart + result + conditionalEnd;

tasks/usemin.js

@@ -11,7 +11,14 @@ var inspect = function (obj) {
 //  - the default one
 var getFlowFromConfig = function(config, target) {
   var Flow = require('../lib/flow');
-  var flow = new Flow({ steps: {'js': ['concat', 'uglifyjs'], 'css': ['concat', 'cssmin']}, post: {}});
+  var flow = new Flow({ steps: {
+    'js': ['concat', 'uglifyjs'],
+    'css': ['concat', 'cssmin'],
+    'libs2min': ['libs2min'],
+    'libs': ['libs'],
+    'remove': [],
+    'void': []
+  }, post: {}});
   if (config.options && config.options.flow) {
     if (config.options.flow[target]) {
       flow.setSteps(config.options.flow[target].steps);