lint and a few issues that seem quite serious

[pirxpilot]

My code tripped on the issue fixed by 6a5d9f7 - using undefined var in swap(). So I tried to add some (very lax) linting. I think it found couple of non-trivial issues - then again I might be missing something obvious here. BTW: make lint is still not happy, but I thought I'd just send a PR with things that do not seem to be cosmetic in nature.