Use std::vector<string> instead of QStringList in main()

In an effort to convert core to C++ structures.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/CMakeLists.txt

@@ -172,6 +172,7 @@ set(SUBSURFACE_CORE_LIB_SRCS
 	string-format.cpp
 	strtod.c
 	subsurface-float.h
+	subsurface-string.cpp
 	subsurface-string.h
 	subsurfacestartup.cpp
 	subsurfacestartup.h