Dev

**New options:**
```js
closeOther: true, //Allow multiple sections to be open(boolean)
activeIndex: false //Active section. The section index(starting from 1)(integer or false)
```
**New files:**
`css/smk-accordion.less` - Less, CSS pre-processor.
`js/min/smk-accordion.min.js` - plugin minified file

**New features:**
* Multiple sections open.
* Init multiple accordions with the same class.
* Added `activeSection` option. No need anymore for `.acc_active` class.
* Minimum markup. No need anymore for `.accordion_in`, `.acc_head`, `.acc_content`. Just make sure to keep the markup clear like this:
```html
<div class="accordion_selector">
	<!-- Section 1 -->
	<div>
		<div> Section 1 </div>
		<div> <!--TEXT--> </div>
	</div>
	<!-- Section 2 -->
	<div>
		<div> Section 2 </div>
		<div> <!--TEXT--> </div>
	</div>
</div>
```