[ns] new ns modules available

[Limin Wang <lmwang@CS.Princeton.EDU>]

Glad to announce that another work based on ns-2 gets published on
Sigmetrics'01 next week.

Understanding TCP Vegas: A Duality Model

Related codes are now available at:
http://www.cs.princeton.edu/~lmwang/ns-module/

source/ directory includes corresponding .h .cc file
tcl-ex/ directory includes the tcl scripts used in the paper for
Vegas+REM case

These should work on ns-2.1b6 without problems. However, since some
changes (almost only add-ons) are made to tcp.h and ns-default.tcl, some work
needs to be done if you want to use them under ns-2.1b8 or ns-2.1b7; but
shouldn't be heavy-weight. If there's a problem, let me know.

Thanks to all ns members!

Limin