Remove unneeded function

This functions should have been removed when the callback-type traversal
was removed.
Add macros for traversals

This patch adds quick 'foreach' macros for simple tree traversal
Merge branch 'master' into dev
Removing current_state
Initial refactoring of user system

This patch refactors the code for storing the online users to use a
rbtree, as well as modifies it to storing 'struct irc_user' objects,
which hold the actual username as well as other user flags.
Removing unneeded variable
Refactoring reply handler setup

This refactor removes the REPLY_HANDLER macro, and moves all the reply
handlers to being static functions internal in ./src/replies.c . The
reply_handler_list[] is still extern, so nothing is broken by this
change (The reply handler list contains the addresses of all the now
static functions, they're accessed via function-pointers.) They shouldn't
be called directly anyway and their inclusion in the header was a
mistake.

Also removed was the reply_handler_count. It was never used and never
set since the reply_handler_list is null terminated (One should check
for a null function pointer and then bail).
Initial commit of user system

This is the initial patch for adding and handling users on channels.

A major refactor of the project is planned, so ATM it's a bit messy.
Setup unit test framework

Unit tests can now be added and run via:

make test

The test framework works via compiling straight in with the .o files
from ./src. Tests are defined in ./test/test.mk, where the ./src/*.c
files as well as the associated ./test/*.c file are speceficed, and all
of that is compiled together with ./test/test.c which includes some
helpful functions for running the framework. the ./test/run_tests.sh
script takes care of running each unit test within valgrind.
Make Travis run unit tests
Small spacing change to ./test/run_tests.sh
Quick fix to ./include/buf.h

A 'ptr' argument to a macro didn't have paren's around it, resulting in
an error if you try to supply it with something like "&buf".
Updating README.md file with more information.