Change history of Practical Introduction to Upvar and Uplevel

Rev	Date	Modified by	Minor edit	Spam	WikiText	Revert to
4	2002-10-03 11:57:43	68.50.162.69	no	no	4	4
3	2002-10-03 11:56:47	68.50.162.69	no	no	3	3
2	2002-10-03 11:56:07	68.50.162.69	no	no	2	2
1	2002-10-03 11:54:56	68.50.162.69	no	no	1	1
0	2002-10-03 11:51:03	68.50.162.69	no	no	0	0