Logging Panic Handler (mc-sgx-panic-log)

[nick-mobilecoin]

• Add untrusted side of stderr from enclave #15
• Rename mc-sgx-io to mc-sgx-io-untrusted #21
• Add mc-sgx-io #22
  • Should we derive ocall function signature from edl output? Captured in Consider ergonomics around dependent OCALLs #52
• Add mc-sgx-panic-log #24
• Use a static buffer for the panic stderr instead of allocating a String This will be handled in Thread (mc-sgx-sync) #29 done in Use a static buffer for panic messages #41
• Merge panic-abort and panic-log crates into mc-sgx-panic #48
  Re-evaluate the loop{} used for logging panic handler. Discussion from Use a static buffer for panic messages #41 (comment)
  The loop will keep the thread going indefinitely, but not actually stop it. The current implementation was modeled after, https://doc.rust-lang.org/nomicon/panic-handler.html, which doesn't seem to halt the thread, but more or less spins it off into oblivion.