exception: Use built-in HTTP response codes

PHP >= 5.4 provides a built-in function to generate valid HTTP
error header including the error description: http_response_code()

See: http://php.net/manual/en/function.http-response-code.php
See also: https://stackoverflow.com/a/12018482

This commit removes the '\Http' utility class and replaces all
calls to 'Http::getMessageForCode()' by 'http_response_code()'

lib/Exceptions.php

@@ -1,64 +1,6 @@
 <?php
 class HttpException extends \Exception{}
 
-/**
-* Not real http implementation but only utils stuff
-*/
-class Http{
-
-	/**
-	* Return message corresponding to Http code
-	*/
-	static public function getMessageForCode($code){
-		$codes = self::getCodes();
-
-		if(isset($codes[$code]))
-			return $codes[$code];
-
-		return '';
-	}
-
-	/**
-	* List of common Http code
-	*/
-	static public function getCodes(){
-		return array(
-			200 => 'OK',
-			201 => 'Created',
-			202 => 'Accepted',
-			300 => 'Multiple Choices',
-			301 => 'Moved Permanently',
-			302 => 'Moved Temporarily',
-			307 => 'Temporary Redirect',
-			310 => 'Too many Redirects',
-			400 => 'Bad Request',
-			401 => 'Unauthorized',
-			402 => 'Payment Required',
-			403 => 'Forbidden',
-			404 => 'Not Found',
-			405 => 'Method Not',
-			406 => 'Not Acceptable',
-			407 => 'Proxy Authentication Required',
-			408 => 'Request Time-out',
-			409 => 'Conflict',
-			410 => 'Gone',
-			411 => 'Length Required',
-			412 => 'Precondition Failed',
-			413 => 'Request Entity Too Large',
-			414 => 'Request-URI Too Long',
-			415 => 'Unsupported Media Type',
-			416 => 'Requested range unsatisfiable',
-			417 => 'Expectation failed',
-			500 => 'Internal Server Error',
-			501 => 'Not Implemented',
-			502 => 'Bad Gateway',
-			503 => 'Service Unavailable',
-			504 => 'Gateway Time-out',
-			508 => 'Loop detected',
-		);
-	}
-}
-
 /**
  * Returns an URL that automatically populates a new issue on GitHub based
  * on the information provided