retab
Fix warnings

This compiles warning-free for me on Linux now. Only one of those
warnings was scary (although it was legit-uninitialized-use scary,
which is pretty scary!), but there's this broken window theory...
Introduce some more warnings

Actually this only causes a few missing field initializer warnings to
show up in the jet code. I disabled sign-compare and unused-parameter
outright because they were too noisy.
Merge pull request #212 from mrdomino/master

screw around with the warnings, fixing some, introducing others