Moved around the IRC modules

This will support factoring the bot into several "applications".

diff --git a/src/irc_channel_sup.erl b/irc/irc_channel_sup.erl
similarity index 100%
rename from src/irc_channel_sup.erl
rename to irc/irc_channel_sup.erl

diff --git a/src/irc_conn.erl b/irc/irc_conn.erl
similarity index 100%
rename from src/irc_conn.erl
rename to irc/irc_conn.erl

diff --git a/src/irc_pid_cache.erl b/irc/irc_pid_cache.erl
similarity index 100%
rename from src/irc_pid_cache.erl
rename to irc/irc_pid_cache.erl

diff --git a/src/irc_sup.erl b/irc/irc_sup.erl
similarity index 100%
rename from src/irc_sup.erl
rename to irc/irc_sup.erl

diff --git a/src/irc_user_sup.erl b/irc/irc_user_sup.erl
similarity index 100%
rename from src/irc_user_sup.erl
rename to irc/irc_user_sup.erl