Don't call updateInfo from enumerateAuxiliaryVector.

updateInfo calls enumerateAuxiliaryVector itself, which results in an
infinite recursion.
Add a small note about thread creation and ptrace flags.
Use std::fclose() in ProcFS.cpp.

This is just a cosmetic change to use std::fclose() instead of fclose()
everywhere.
Use a dedicated stack for crash handlers.

This allows us to have our crash handler display its message even when
the stack pointer is busted (e.g.: infinite recursion in ds2).
Make sure we fclose everything in ProcFS.cpp.
Use nullptr instead of NULL.