"make uninstall" without errors
Seperate between python2 and python3 to ensure complete removal of files when doing "make uninstall"
Merge pull request #301 from jdede/fix-uninstall

tools: Fix "make uninstall" for CoAP, some python files, and 6lowpan tests.
nesc: bump package version to 1.3.6
BLIP: fix bad merge

I clearly missed this at some point. UDPEcho should compile now.
CoapBlip: fixed RPL compile error.

Need to specify the objective function in RPL now. It used to be an ugly
define buried in the RPL code.