initial reformatting of comments for Doxygen

savemem.cpp

@@ -1,6 +1,11 @@
-// Hyperbolic Rogue -- smart memory cleaner
+// Hyperbolic Rogue -- memory saving
 // Copyright (C) 2011-2018 Zeno Rogue, see 'hyper.cpp' for details
 
+/** \file memory.cpp
+ *  \brief memory saving: memory saving mode, memory warnings, etc.
+ */
+
+
 namespace hr {
 
 #if HDR