use Colors.Normal for NAMEs in PyColorize

LightBG/Linux previously hard-coded White&Black for names, rather than just using
the foreground color.  This maximized the penalty for using the wrong
color scheme on a white or black background.

IPython/utils/PyColorize.py

@@ -78,7 +78,7 b' LinuxColors = ColorScheme('
     token.OP         : Colors.Yellow,
     token.STRING     : Colors.LightBlue,
     tokenize.COMMENT : Colors.LightRed,
-    token.NAME       : Colors.White,
+    token.NAME       : Colors.Normal,
     token.ERRORTOKEN : Colors.Red,
 
     _KEYWORD         : Colors.LightGreen,
@@ -93,7 +93,7 b' LightBGColors = ColorScheme('
     token.OP         : Colors.Blue,
     token.STRING     : Colors.Blue,
     tokenize.COMMENT : Colors.Red,
-    token.NAME       : Colors.Black,
+    token.NAME       : Colors.Normal,
     token.ERRORTOKEN : Colors.Red,
 
     _KEYWORD         : Colors.Green,