lib/difflib.py:

Added support for generating side by side differences.  
Intended to be used for generating HTML pages but is 
generic where it can be used for other types of markup.

tools/scripts/diff.py:

Added -m option to use above patch to generate an 
HTML page of side by side differences between two 
files.  The existing -c option when used with the new -m 
option controls whether contextual differences are 
shown or whether the entire file is displayed (number of 
context lines is controlled by existing -l option).

NOTES:
(1) Textual context diffs were included as requested.  In 
addition, full and contextual HTML side by side 
differences (that this patch generated) are also included 
to assist in analyzing the differences and showing an 
example.

(2) If this functionality is worthy of inclusion in the 
standard python distribution, I am willing to provide more 
documentation or make modifications to change the 
interface or make improvements.

(3) When using Internet Explorer some font sizes seem 
to skew things a bit.  Generally I've found the "smallest" 
to work best.  If someone knows why, I'd be interested 
in making any necessary adjustments in the generated 
HTML.