Finish adding proper logging support to capture

[bgottula]

I added logging support recently with spdlog, however this was limited to the portions of the code I was working on at the time, mainly in camera.cpp.

Do the following:

• Replace printf with logging consistently throughout the codebase
• Add support for logging to a file rather than just the default console output
• Add support for changing the log levels and log filename via program options
• Make sure we're using the thread-safe _mt loggers