Add Conrainer#removeAll()

lib/container.js

@@ -297,6 +297,18 @@ class Container extends Node {
         return this;
     }
 
+    // Remove all children in node.
+    //
+    //   css.removeAll();
+    removeAll() {
+        for ( var i = 0; i < this.nodes.length; i++ ) {
+            this.nodes[i].parent == undefined;
+        }
+        this.nodes = [];
+
+        return this;
+    }
+
     // Return true if all nodes return true in `condition`.
     // Just shorcut for `nodes.every`.
     every(condition) {

test/container.js

@@ -493,6 +493,15 @@ describe('Container', () => {
 
     });
 
+    describe('removeAll()', () => {
+
+        it('removes all children', () => {
+            this.rule.removeAll();
+            expect(this.rule.toString()).to.eql('a { }');
+        });
+
+    });
+
     describe('any()', () => {
 
         it('return true if all children return true', () => {