Merge branch 'feature/gnuplot-raw-writer' into 'develop'

doc/userdoc.org

src/language/modules/SchemeModule.cpp

src/language/modules/WriterModule.cpp

src/output/CMakeLists.txt

src/output/GnuplotWriter.cpp

src/output/GnuplotWriter.hpp

src/output/GnuplotWriter1D.cpp

src/output/GnuplotWriter1D.hpp

src/output/GnuplotWriterBase.cpp

src/output/GnuplotWriterBase.hpp

src/output/GnuplotWriterRaw.cpp

src/output/GnuplotWriterRaw.hpp