Add clang-format configuration file.
Correct htonll macro detection in CMake.

CMake's check_function_exists() only checks for a symbol being defined in a
library, and does not cover the instance where a function may be defined as a
macro a header. Use check_symbol_exists() to check arpa/inet.h header for symbol
existance of htonll.

This fixes #200
Ignore build directories.
Fix: remove superfulous assignment in amqp_socket.c

sockfd is assigned, then assigned again unconditionally without being read
from. There's no point in this statement, so lets get rid of it.
FIX: don't range-check channel_ids.

Even if a channel_max is specified, channel_ids can be any number, so don't
range-check channel_ids received. At present this gets rabbitmq-c back into
compliance with the way the RabbitMQ broker works.

See issue #187, #195

To correctly enforce channel_max from the client side, rabbitmq-c would need to
track open channels, which is a bit more involved to do correctly.
Preparation for v0.5.1 release.
Bumping version for development.
autoconf: look for htonll in arpa/inet.h

htonll maybe defined as a macro, look for it in the arpa/inet.h. CMake build
system already does the right thing.

Fixes #206
Add usable YCM configuration file.
Merge pull request #1 from alanxz/master

update project