Folllow freedesktop specs for files created/stored by Deluge

[Cas]

It would be good if rather than dumping everything in config dir, we follow the Freedesktop specs:

• XDG_DATA_HOME - user specific data files
  • state files
  • ssl dir
  • plugin eggs dir

• XDG_CACHE_HOME - non-essential cached data
  • icons dir
  • blocklist cache

• XDG_RUNTIME_DIR - non-essential runtime files
  • ipc dir
  • pid files

• XDG_CONFIG_HOME - user specific configuration files
  • conf files

The only question mark is what .torrent files should be classified as.

Reference: ​Freedesktop

[Cas]

From duplicate #2366

The specification ensures that a pid file will not survive on a reboot or login/logout cycle. Thus, using $XDG_RUNTIME_DIR remedies this situation.

[Cas]

Reference code for Runtime dir: ​http://www.nullege.com/codes/search/xdg.BaseDirectory.get_runtime_dir?fulldoc=1

[Cas]

Milestone renamed

[DjLegolas]

Aren't the .torrent files part of the user data?
Currently they are stored in the state directory, so why not leave them there?