Spike: feature parity with helium forks of 1301 and 1302 pktfwd

[pritamghanghas]

The helium forks of pktfwd seem to have some changes. Most of them are small fixes but we saw a few that change buffer size to accommodate larger payloads.
it might be worthwhile to investigate those changes and see if we need a backport merge to our repo. Helium and our repo are forked from same upstream LoraNet repo. Merge shouldn't be a big issue if required.

[shawaj]

Related to #23