Make the output of the requirement file generator determinable

When I recompile the api the order of the generated requirements
almost always change. Over time someone would have probably accidentally
committed a reorder, ending in useless commits. A fix for this is to
order all input files, which will always result in the same output.

project/APIUtility.scala

@@ -60,6 +60,7 @@ class APIUtility(logger: ManagedLogger) {
           }
         }
       }.filter(_.isDefined).map(_.get)
+        .sortBy(x => x.file.getAbsolutePath)
 
     RequirementsFile(new File(sourceDirectory, configurationFolder), "Input", filesWithRequirements.head).createFile()
     RequirementsFile(new File(sourceDirectory, configurationFolder), "Output", filesWithRequirements(1)).createFile()