Updating the TwitterOAuth Class to support different endpoints aside Twitter's

The original library was updated to allow the API endpoints to be modified if necessary. This would allow other API's with similar endpoints and structure as Twitter's API to benefit from the Library. A example for this is the 500px.com API.

The library was modified to allow ```host```, ```acccessTokenUrl```, ```authenticateURL```, ```authorizeURL``` and ```requestTokenURL```
to be updated or new values where it's default's value are Twitter's original API endpoints and host.

The functions bellow are now deprecated:

```
	accessTokenURL()
	authenticateURL()
	authorizeURL()
	requestTokenURL()
```

and they were replaced by:

```
	* @param string $type Default's to access. Values: <access_token>, <authenticate>, <authorize> and <request_token>
	getUrl($type = 'access_token')
```

A new function was added so the ```host```, ```acccessTokenUrl```, ```authenticateURL```, ```authorizeURL``` and ```requestTokenURL```
can now be set from application side:

```
	* @param string $param Accepted values: <host>, <accessTokenUrl>, <authenticateUrl>, <authorizeUrl>, <requestTokenUrl>
	* @param string $value (optional) If empty will set the param with null
	setParam($param, $value = null)
```

This new library was tested prior making the pull request.

Questions I'm also available in Twitter: @mcloide