[Tinyos Core WG] new tag

[Philip Levis]

There were a couple of (late!!!!) last-minute checkins after I tagged  
with rc1, so I've now tagged with an rc2. Please do your testing with  
tag:

rc_2_tinyos_2_1_0

Apologies if you've already started testing. I would have had to tag  
with rc2 regardless, so you would have needed to repeat regardless.

Also, a note: no-one should *ever* move the release testing tags. Once  
applied, they should never change. Instead, if there modifications, I  
apply a new release candidate (e.g., rc3).

Finally, application owners have an additional responsibility. TEP 4  
lays out how active message IDs should be allocated. If you own an  
application, you should check that it follows TEP 4. Basically, this  
means stuff in apps should have AM ids between 128-255; below 128 is  
reserved for tos/. If your application has an ID in the range of  
0-127, you should change it and apply that change to the tree. When I  
apply rc3 we can do a quick sanity check.

Phil