document save_history command and a few more small tweaks

tools/lammps-shell/README

@@ -88,6 +88,10 @@ regular LAMMPS commands:
 - help (or ?)    print a brief help message
 - history        display the current command history list
 - clear_history  wipe out the current command history list
+- save_history <range> <file>
+                 write commands from the history to file.
+                 The range is given as <from>-<to>, where <from> and <to>
+                 may be empty. Example: save_history 100- in.recent
 - source <file>  read commands from file (same as "include")
 - pwd            print current working directory
 - cd <directory> change current working directory (same as pwd if no directory)

tools/lammps-shell/lammps-shell.cpp

@@ -666,7 +666,7 @@ int main(int argc, char **argv)
     std::string trimmed;
 
     lammps_get_os_info(buf, buflen);
-    std::cout << "LAMMPS Shell version 1.0  OS: " << buf;
+    std::cout << "LAMMPS Shell version 1.1  OS: " << buf;
 
     if (!lammps_config_has_exceptions())
         std::cout << "WARNING: LAMMPS was compiled without exceptions\n"