Added InfoWarning in the case when no package is installed

Author: Alexander Konovalov

lib/package.gi

@@ -1422,6 +1422,12 @@ InstallGlobalFunction( LoadPackage, function( arg )
     if not IsBound( GAPInfo.PackagesInfo.( name ) ) then
       LogPackageLoadingMessage( PACKAGE_DEBUG,
           "no package with this name is installed, return 'fail'", name );
+      if InfoLevel(InfoPackageLoading) < 4 then
+        Info(InfoWarning,1, name, " package is not available");
+        Info(InfoWarning,1, "Check that the package name is correct and it is located in the 'pkg'");
+        Info(InfoWarning,1, "subdirectory of your GAP installation or in the 'pkg' subdirectory");
+        Info(InfoWarning,1, "of at least one of the directories given by 'GAPInfo.RootPaths'");
+      fi;
       return fail;
     fi;