Fix pointer truncation during process iteration

In similar vein to the migration issue, incognito was crashing when
running under SYSTEM processes (such as lsass.exe). This was because
of a pointer truncation problem when processes were being enumerated.

There was also some other quirky logic going on, but nothing too
damaging. I added some other simple code tidies while I was in there.
Remove unused param, force 'treat warnings as error'

For some reason this project setting wasn't present in incognito.
Merge branch 'upstream/master' into incognito_pointer_truncation_fix
Land #66, fix incognito ptr truncation