Added CI files.

.editorconfig

@@ -0,0 +1,19 @@
+root = true
+
+[*]
+indent_style    = tab
+indent_size     = 4
+end_of_line     = lf
+max_line_length = 100
+insert_final_newline     = true
+trim_trailing_whitespace = true
+
+[include/bgfx/c99/*.h]
+indent_style = space
+
+[*.ninja]
+indent_style = space
+
+[*.md]
+trim_trailing_whitespace = false
+max_line_length = 80