Clean up

This is an attempt to clean up the repository a little bit. In this branch I did the following:

* Removed unesessary files and folders
    * The `__MACOSX` folder comes from a ZIP file created on a Mac and contains meta information about the files in the ZIP archive. Extracted on a Mac it will be removed automatically. On Windows / Linux it remains.
    * In `GMIMedia/bin/` are the compiled files. These should not be part of version control.
    * The `.DS_Store` files contain meta information on a Mac and should also not be included in version control.

* Changed every line ending from the one used in Windows (\r\n) to the Unix one (\n). The line endings were mixed over multiple files. There should be only one type. The `GMIMedia/.gitattributes` configuration already specified git should use the Unix one ( `* text=auto` )

* Added an `.editorconfig` file which specifies which configuration should be used by an editor. Note that a plugin for your editor is needed for this to work. ( see <http://editorconfig.org/> )

* Converted every tab to spaces. Again they were mixed together.

* Formatted the code in IntelliJ and also performed some other minor changes as renaming the images in `GMIMedia/res/drawable-mdpi/` to more expressive country codes.

If you want I can also squash the commits into one. With multiple commits I thought it can be clearer seen what was changed.