Added more MIME Types in `inc/lib_filestorage.php`

Here the types added:
  * Flac / Ogg [1]
  * GZip / Tar / Tar+GZip
  * PDF / SVG / Tiff
  * JavaScript

Other little changes:
  * I changed the ordered to be alphabetical (by extension)
  * Using single quotes instead of double quotes for strings
  * Indentation

[1]: http://wiki.xiph.org/MIME_Types_and_File_Extensions
[2]: http://www.asciitable.it/mimetypes.asp