refactor(createStyledComponent): removed taget checks

feat(tests): restored skipped tests

Author: codebender828

src/models/StyledComponent.js

@@ -1,6 +1,5 @@
 import css from '../constructors/css'
 import normalizeProps from '../utils/normalizeProps'
-import isVueComponent from '../utils/isVueComponent'
 
 export default (ComponentStyle) => {
   const createStyledComponent = (target, rules, props) => {
@@ -38,9 +37,9 @@ export default (ComponentStyle) => {
             children.push(createElement('template', { slot }, this.$slots[slot]))
           }
         }
-        const element = this.$props.as
+
         return createElement(
-          isVueComponent(target) ? target : element || target,
+          this.$props.as || target,
           {
             class: [this.generatedClassName],
             props: this.$props,

src/test/extending-components.test.js

@@ -78,8 +78,7 @@ describe('extending components', () => {
     expectCSSMatches('.a {color: blue;}.a > h1 {font-size: 4rem;} .b {color: red;}')
   })
 
-  // Skipped because test fails
-  xit('should keep default props from parent', () => {
+  it('should keep default props from parent', () => {
     const parentProps = {
       color: {
         type: String,