BUG: double-free in ssl-socket on connect failure

In amqp_ssl_socket_open() set self->ssl to NULL after SSL_free() to
avoid calling SSL_free() on a SSL object that has already been freed.

This fixes #129 crash while call amqp_destroy_connection() with ssl
FIX: amqp_open_socket not defined.

This fixes a regression introduced in 6ad770dc where the
amqp_open_socket() function is no longer defined.
Provide defaults values for amqp_login

Provide default values for:
 - channel-max as AMQP_DEFAULT_CHANNEL_MAX 0 = unlimited
 - frame-size as AMQP_DEFAULT_FRAME_SIZE 131072 = 128KB
 - heartbeat as AMQP_DEFAULT_HEARTBEAT 0 = disabled
Add compile and runtime library version functions
Document public API
FIX: bring autotools build system up to date

Remove the amqp_framing.c/.h regeneration logic as it breaks make dist.
Bring the EXTRA_DIST list up to date with whats in the repo
FIX: missing files in dist package
Updating version numbers for release of v0.4.0
Bumping revision for development
Add amqp_get_broker_properties() function

Add function to return the properties table advertised by the broker on
connection to the broker.
FIX: destroy amqp_envelope_t in consumer example

Make sure to destroy the envelope object in the amqp_consumer.c example
CMake: correct generation of librabbitmq.pc

Fix CMake code that substitutes librabbitmq.pc to be correct.
Removing distro-specific packaging components

It doesn't seem possible to write a distribution-agnostic .spec or .deb
build files that won't get changed by the distribution anyway. Instead
I'm going to let the downstream consumers create their own packaging
Non-exclusive queue declaration in amqp-consume.

Declare non-exclusive queue by default, which allows task queue
round-robin publishing when binding to a "direct" typed exchange with
a routing key matching the publisher's one and the queue name.
The "-d" option is replaced with a "-x" option to explicitly declare
an exclusive queue if needed.
amqp_socket_close() should not be a public fn
FIX: use correct buf/len when re-starting send()

Fix a bug that manifested itself by the broker disconnecting the client
with an invalid_frame_end_marker error. The cause was when send()
returned less than the size of the buffer to be sent we weren't using
the correct parameters when restarting the send call.
Prep for v0.4.1 release
Bumping version due to v0.4.1 release
Add amqp_basic_nack() API function
* tools/CMakeLists.txt: Fix missing POPT_INCLUDE_DIRS variable.