Added t8.pl that test case sensitivity issues

Made some change in the .cpp code in order to be able to test
the code when the file system is case sensitive
Utility: move raiseDisalog to owncloudGui

Reduce the GUI dependency in the Utility namespace used by libowncloudsync
Utility: remove Utility::dataLocation

It is used only from one location, so put the code there
Utility: Move showInFileManager in its own file

And get rid of GUI in the Utility namespace
Remove undeeded include
Move Folder, FolderMan, and FolderWatcher outside of owncloudsync

Those class are maintaining the folder for the mirall configuration
They are not usefull in command line clients

Also the FolderWatcher is only used by the folder and not used by the
command line clients
Engine: Do not reset the csync log callback in the engine

It is already set in Folder and we don't want to use the Logger
in command line clients
cleanup the CMakeLists.txt

Headers need not to be added if they are not going to be installed
The list was incomplete anyway, and most of the _HEADERS variables
were even not used
folder: remove TOKEN_AUTH_ONLY

Folder is no longer in the libowncloudsync
Add Q_DECL_OVERRIDE for all function that are overriding something

This was made automatically with
clang-modernize -override-macros -add-override
Define Q_DECL_OVERRIDE for Qt4

That macro is new in Qt5, define it as well when compiling with Qt4
so we can use it in mirall

Note: QNetworkCookieJar::deleteCookie was not existing in Qt4.