Merge pull request #18 from kjokinie/master

Fix issue with ffmemless file descriptor getting closed spuriously
Remove session file reading.

We always get the session bus set up for us properly, and are started after
DBus, so we can rely on it actually being there. Remove all the useless dead
code for reading the Harmattan session file.
Merge pull request #19 from rburchell/master

Remove session file reading.
[ffmemless] Add check for device existence to plugin loading

Ngfd fails to run in SDK as there is no ffmemless device, and
a sink failing init will stop whole ngfd from working. Added
a check to plugin load for the device existance, so we don't
even load the plugin if we can't run it.

Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@jollamobile.com>