Added clang-format (#623)

* added .clang-format
* added names to travis jobs
removed deprecated travis option
* check github action
* added .gitignore

.editorconfig

@@ -0,0 +1,8 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+charset = utf-8
+trim_trailing_whitespace = false
+insert_final_newline = true