Expand log options

[kbembedded]

In https://github.com/kbembedded/msemu/pull/35#discussion_r331761742 it was suggested to expand logging capabilities to have different layers.

e.g. log_debug() would be very very verbose log_trace() would only log/display opcodes executed, still noisy log_warn() to log warnable things (not sure what would fall here) log_info() to always output/log, similar to error but not actually an error log_error() to log critical errors that happen

[kbembedded]

As of current work in refactor/kbe/debug branch, log_debug(), log_trace(), and log_error() are implemented. I think this is about as much of a separation thats possible and is still useful.