Fix issue #24: Pressing 'Spacebar'/'Enter' key does not 'show all dialog lines at once'

This bug is caused by the time-consuming update-per-char drawing operation.
So to fix it, just need to disable the update if user required to skip the
dialog, and update the full screeen at once after all texts are drawn.

text.c

@@ -1356,7 +1356,8 @@ PAL_ShowDialogText(
                text[0] = *lpszText++;
 			   text[1] = 0;
 
-               PAL_DrawText(text, PAL_XY(x, y), g_TextLib.bCurrentFontColor, TRUE, TRUE, FALSE);
+			   // Update the screen on each draw operation is time-consuming, so disable it if user want to skip
+               PAL_DrawText(text, PAL_XY(x, y), g_TextLib.bCurrentFontColor, TRUE, !g_TextLib.fUserSkip, FALSE);
 			   x += PAL_CharWidth(text[0]);
 
                if (!g_TextLib.fUserSkip)
@@ -1375,6 +1376,12 @@ PAL_ShowDialogText(
             }
          }
 
+		 // and update the full screen at once after all texts are drawn
+		 if (g_TextLib.fUserSkip)
+		 {
+			 VIDEO_UpdateScreen(NULL);
+		 }
+
          g_TextLib.posIcon = PAL_XY(x, y);
          g_TextLib.nCurrentDialogLine++;
       }