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