improved code styles #158 (#172)

* use php-cs-fixer instead of phpcodesniffer
* updated scrutinizer config
* adjusted code yules to all files
* updated CONTRIBUTING guidelines

translations/flashmessages.ru.xliff

@@ -26,6 +26,14 @@
                 <source>action.deleted_successfully</source>
                 <target>Запись успешно удалена</target>
             </trans-unit>
+            <trans-unit id="action.deleted.error">
+                <source>action.deleted.error</source>
+                <target>Entry could not be deleted: %reason%</target>
+            </trans-unit>
+            <trans-unit id="invoice.first_template">
+                <source>invoice.first_template</source>
+                <target>You have to create your first template invoice before you can proceed</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>