Add --llc-path and --log-file options

[jimbxb]

Closes #477
Closes #478

[pschachte]

This looks fine, so I'll pull it, despite the problem with the CI system you reported.

[pschachte]

BTW, I don't think logging to /var/log is a good idea, given the intent of /var/log and the purpose of wybemk logging. The former is intended for logging aspects of the normal execution of system programs, while the latter is intended for debugging the compiler. I don't know of any other compilers that log to /var/log.

[jimbxb]

That's probably right.

The main intent of the log file flag was because I'd often find myself routing the logs to a file and analysing that. Scrolling through stderr in the terminal isn't fun, and can slow down the terminal considerably when the verbose loggers are turned on.

[pschachte]

Yep. I always write the log to a file. You've probably seen me accidentally commit a file called LOG to the repo, and then have to delete it later.