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/.
[A] Remove QtXml dependency.
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.
[A] Add EmptyProject BM.
[T] Replace AddTestWrapper with SimpleWrapper.
Add test for quad 20 by 10 mesh.
WIP Direct ExternalData_Add_Test().