[algorithms] Protected algorithm declaration with django filter (closes #417)

beat/web/algorithms/templates/algorithms/edition.html

@@ -78,7 +78,7 @@ function setupEditor(algorithm, dataformats, libraries)
 
 
   // Options
-  var declaration = JSON.parse('{{ declaration|safe }}');
+  var declaration = JSON.parse('{{ declaration|escapejs }}');
 
   var checkbox_analyzer   = $('#checkbox_analyzer');
   var checkbox_splittable = $('#checkbox_splittable');