Search for user specific config path and merge with the default config

Better guard against null values in user config
If the user set background cannot be loaded fall back to the default one
Fix build deps
fix crash on double pam handle free

fixes sddm/sddm#145
Merge pull request #146 from MartinBriza/pamcrash

fix crash on double pam handle free
Merge pull request #144 from davidedmundson/debian_build_deps

Fix build deps
Merge pull request #143 from davidedmundson/custom_background

Restore custom background support from sddm-kcm
Fix xauth annoying error
Merge pull request #147 from Teknocrat/xauth-fix

Fixes xauth warning about authority file not existing.
Add missing semicolon.
Don't set GDMSESSION as it is not used anymore.

Fixes #138.
improve .travis.yml

it's little bit messy, but it works
infrastructure is ready for clang, but for now build always fail
Merge pull request #149 from iXit/master

Fixes autobuilds using travis.
Added travis build status.
Open log only once and fallback to stdout when unable to open

Make QFile static to avoid opening and closing it for every log
message which will be rather slow.

Also, if it's not possible to open the log file fallback to
stdout to avoid losing log messages.
This is useful in test mode which runs as normal user.
translate japanese
update JA translation
Merge pull request #152 from plfiorini/log

Open log only once and fallback to stdout when unable to open
Support logging to journald if enabled

Add support to journald logging that provides us much more information
such as code line and function, process command line, etc...
Logging works just like before when running interactively.

Since the DAEMON or GREETER prefix are not useful when logging to journald
and there was not even consistency between them, we now have two message
handlers respectively for daemon and greeter.

Those message handlers prepend the correct prefix to the message when
logging to file or stdout.  As a result all log messages don't need to
provide those prefixes anymore.
Merge pull request #157 from plfiorini/journald

Support logging to journald if enabled