Refactor main()

[th-we]

Refactored ~200 lines of code into task specific functions:

• update_key_state()
• open_log_file()
• log_event()
• post_log()
• log_loop()

Motivation: Make the code more reusable for slightly different logging tasks. (My use case: log key frequency and n-gram statistics, respecting typing timing and pauses.)

[kernc]

I haven't diffed all the hunks, but the split up looks reasonable, and what little I tested still seems to work.

Thanks.