Added a new configuration variable, PHPCI_BUILD_ROOT_DI.

This variable allows to change where the build happens.
It defaults to PHPCI_DIR.'PHPCI/build/'.

Moved build path calculate and build removal into the Build class.

Also remove the build directory when deleting the build.

Close #834

PHPCI/Model/Build.php

@@ -217,4 +217,28 @@ class Build extends BuildBase
     {
         return array($builder, $file, $line, $message);
     }
+
+    /**
+     * Return the path to run this build into.
+     *
+     * @return string
+     */
+    public function getBuildPath()
+    {
+        return PHPCI_BUILD_ROOT_DIR . $this->getId();
+    }
+
+    /**
+     * Removes the build directory.
+     */
+    public function removeBuildDirectory()
+    {
+        $buildPath = $this->getBuildPath();
+
+        if (!is_dir($buildPath)) {
+            return;
+        }
+
+        exec(sprintf(IS_WIN ? 'rmdir /S /Q "%s"' : 'rm -Rf "%s"', $buildPath));
+    }
 }