* Smart indentation support

Indentation support can be set to `smart` (default), `preserve` or `none` in the `gui` section of the config file.
Readme file has been updated accordingly.

Heavily based on SciTe official implementation.

* Make linux flavour use c++11

* Fix the wrong ident and make code more readable

* Rewrite in c++98, name config key “autoIndent”