Use the SessionCommand from the config instead of the one from cmake

Closes #263
Namespace'd everything auth related
Fix HelperApp compilation
Added a fake AuthPrompt::response property getter to keep the MOC parser happy

Closes #208
Fixed a bunch of typos in the README
Remove Qt 4 leftovers
Log user session command
For sessions, prefer .desktop files if they exist

When using sessions, prefer .desktop files, if they exist.

This also allows for example to configure Session=plasma
in the autologin section, instead of having to add the
.desktop extension.

[ChangeLog][Daemon][Display] Automatically append .desktop extension
to sessions if the corresponding file exists.
Log desktop file
Fix session index check
Estonian translation

Add Estonian translation from Jüri Ivask <Jyri.Ivask@mail.ee>

[ChangeLog][Translations] Added Estonian translation.
Replace "extention" with "extension"

Fix spelling error.
Remove unused code

We're already in an else branch of if (daemonApp->testing())
Move sigusr1 handling to be in Xserver code and be more semantically correct
Fix test mode.

With Xephyr there is no usrsignal, so we need to emit start manually
Merge pull request #270 from davidedmundson/asdf

Fix sddm-test mode
Fixed "avaialble" typo in man pages
Merge pull request #278 from eyolfson/typo-fix

Fixed "avaialble" typo in man pages
Never try to login as the user SDDM
Merge pull request #279 from davidedmundson/block_sddm_user

Never try to login as the user SDDM