Added all required headers for 'install' target

Added conf.producer.max_outq_msg_cnt: allows the application to limit the outgoing message queue size.

Created a small c++ librdkafka produce wrapper. 

(cherry picked from commit 2103defc)

Added c++ headers in the project Makefile
	modified:   Makefile

Remove some duplicated entry in examples/Makefile
	modified:   examples/Makefile

Some fixes done here.
	modified:   examples/rdkafka_example.cpp

Updated some not-C++ compilant code
	modified:   rdaddr.h

	renamed:    c++/rdkafka.h -> rdkafkacpp.h

	new file:   ../c++/rdkafka.h
	modified:   .gitignore
	modified:   Makefile
	new file:   rdkafka_example.cpp
	modified:   ../rdaddr.h

Calling application must ignore or handle SIGPIPE to avoid termination if connection drops. (issue #2)

Bugfix in example code

Comment: strncpy() does not null terminate if it fill all bytes up to len.  This fixes this issue. (reported by: andoma)

In producer example, use a 2K on-the-stack buffer to read into from stdin, but then make a copy before passing it into librdkafka for consumption.