Methods getAdditionalParams & setAdditionalParams which allow the user to pass additional parameters to the encoding request (#284)

* Modification of the format Video to add additional parameters based on user's desire
* Update of the README
* Working version of this feature. Still needs tests
* Fixing the tests of FFMPeg\Media\Video
* Setting up tests for the additionalParams feature
* Correction des tests
* Modifying tests. They work locally but not on Travis.
* Still trying to understand why Travis is throwing errors when PHPUnit is not.
* Add the additional params at the end of the command
* Fixed the tests and the way we add the parameters
* We remove log files

src/FFMpeg/Format/Video/DefaultVideo.php

@@ -32,6 +32,9 @@ abstract class DefaultVideo extends DefaultAudio implements VideoInterface
     /** @var Integer */
     protected $modulus = 16;
 
+    /** @var Array */
+    protected $additionalParamaters;
+
     /**
      * {@inheritdoc}
      */
@@ -94,6 +97,31 @@ abstract class DefaultVideo extends DefaultAudio implements VideoInterface
         return $this->modulus;
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function getAdditionalParameters()
+    {
+        return $this->additionalParamaters;
+    }
+
+    /**
+     * Sets additional parameters.
+     *
+     * @param  array                    $additionalParamaters
+     * @throws InvalidArgumentException
+     */
+    public function setAdditionalParameters($additionalParamaters)
+    {
+        if (!is_array($additionalParamaters)) {
+            throw new InvalidArgumentException('Wrong additionalParamaters value');
+        }
+
+        $this->additionalParamaters = $additionalParamaters;
+
+        return $this;
+    }
+
     /**
      * {@inheritdoc}
      */