Implement "Hello, world" functionality

The bot now successfully connects to Rizon, joins #ircbottestrelam,
and responds to messages beginning with "!test" with the sentence
"The quick brown fox jumps over the lazy dog." It handles PING/PONG
events, but not VERSION requests. It ignores all messages for the
first thirty seconds of connection, instead of parsing the welcome
messages.
Update .gitignore to ignore temp ~ files left by vim
Update .gitignore to ignore .swp files
Reimplement basic message-parsing functionality

PING/PONG response NYI under the new system. Currently bot will echo
to stdout its parsed versions of each message sent at least 30 seconds
after the initial connection attempt.
Set up framework for basic command handling

The new file codelist.go contains a map from IRC commands such as
"PING" or "PRIVMSG" to a function that handles each command. The only
fully-implemented commands so far are responses to PING and VERSION.
Any message containing the command PRIVMSG will echo the in-memory
representation of the message to stdout. All other commands are
not-yet-implemented. The file parseMessage_test.go provides basic
testing functionality for these commands.

The logic in main.go was changed to accommodate this new, more
extensible setup.