Add README and license information for bison and flex

Compiler/Tools/COPYING.flex

+Flex carries the copyright used for BSD software, slightly modified
+because it originated at the Lawrence Berkeley (not Livermore!) Laboratory,
+which operates under a contract with the Department of Energy:
+
+	Copyright (c) 1990 The Regents of the University of California.
+	All rights reserved.
+
+	This code is derived from software contributed to Berkeley by
+	Vern Paxson.
+
+	The United States Government has rights in this work pursuant
+	to contract no. DE-AC03-76SF00098 between the United States
+	Department of Energy and the University of California.
+
+	Redistribution and use in source and binary forms are permitted
+	provided that: (1) source distributions retain this entire
+	copyright notice and comment, and (2) distributions including
+	binaries display the following acknowledgement:  ``This product
+	includes software developed by the University of California,
+	Berkeley and its contributors'' in the documentation or other
+	materials provided with the distribution and in all advertising
+	materials mentioning features or use of this software.  Neither the
+	name of the University nor the names of its contributors may be
+	used to endorse or promote products derived from this software
+	without specific prior written permission.
+
+	THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+	IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+	WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+	PURPOSE.
+
+This basically says "do whatever you please with this software except
+remove this notice or take advantage of the University's (or the flex
+authors') name".
+
+Note that the "flex.skl" scanner skeleton carries no copyright notice.
+You are free to do whatever you please with scanners generated using flex;
+for them, you are not even bound by the above copyright.

Compiler/Tools/README

+The standalone Bison and Flex win32 executables
+were created by Wilbur Streett and can be obtained from:
+http://userpages.monmouth.com/~wstreett/lex-yacc/lex-yacc.html
+
+Bison version 1.24:
+See COPYING.bison for license information.
+The original source distribution for bison can be obtained from the following location:
+http://angleproject.googlecode.com/files/bison.zip
+
+Flex version 2.5.2
+See COPYING.flex for license information.
+The original source distribution for flex can be obtained from the following location:
+http://angleproject.googlecode.com/files/flex.zip
+