Misc: Add an editorconfig

* This is a platform independent config which is
  supported in many editors to set the charset and intendation
  automatically on a per project basis.
* The latin1 charset is a workaround for the MSVC
  editorconfig support which stores utf-8 with bom
  instead of none.

(cherry picked from commit 850fbbd6a9)

.editorconfig

@@ -0,0 +1,11 @@
+[*]
+charset = utf-8
+indent_size = 4
+tab_width = 4
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+max_line_length = 80
+
+[*.{c,h,cpp,hpp,inl}]
+charset = latin1