Fix binary string literal in Access Code

Fixes #11
Remove read-only test (moving to a branch)
Switch everything to require_relative
Be more careful with locking

@paused was being accessed concurrently.  Since it was just a bool it
would have been fine, so this is just for consistency.  (Also, someone
may add more code later on.)
Missed a few require_relatives
Fix hasher gunlock fix
Separate "Connection.handshake" into a mixin
Divide Connection into two classes
Split up GnuTLS library
Connection keepalive
Add connection manager
Don't transfer empty files
Event debouncer
Fix debouncing

Don't share path variable amongst callback instances
Remove inefficient data structure

The old implementation using a hash would go O(N^N), where N is the
number of event categories being debounced.
Move debouncer into scanner

The change monitors should be as unsophisticated as possible
Basic function documentation
Fix scanner test

This was broken when I added the debouncer into the scanner.
Delete access codes once no longer needed
Check user input