adding indigo section
clone rep 141 from 137
add draft for REP 141
feedback on REP 141
more feedback on REP 141
add upgrade path info to REP 141
Change to python 2.7 required

testing against python 3.3 now recommended.
Merge pull request #64 from ros-infrastructure/indigo_update

adding indigo section

It looks like we've reached consensus. Merging.
Merge pull request #66 from ros-infrastructure/rep141

REP 141