fixed indentation and renamed method
renamed gsp-interface to project-interface
Merge remote-tracking branch 'ufz/pr/434' into develop

Conflicts:
	FileIO/XmlIO/Qt/XmlProjectInterface.cpp

Added const and & for filename type.
First OGS simulation main program.
Specify full path in #include.

This is required for an upcoming application.
It was already discussed in #89 and will come up
with more changes as the application grows. So
step by step all #includes will have the full
paths prepended.
Adjust CMake config for command line application.

Previously added OGS directory holds the libOGS
and not the applications. This also separates
the libOGS library from applications.
Move ogs application into Applications/.
Add ctest for ogs executable.
[A] Include copyright and version info.
[A] Make project file argument unlabeled.

This is not an optional argument and the extra flag is not necessary.
Specify arguments help info.
[D] Add Applications dir to doxygen inputs.
Remove eol whitespaces; empty \file doc.
[A] Instatiate QApplication needed for XML interface.
[A] Update for Gsp to Project XmlInterface rename.
Break multiple statements in single line.
WIP add empty test.