Free/Net/OpenBSD have another names for libevent2 headers.
Add #ifdef / #else / #endif to include correct headers.
[build] correct sed usage
[build] fix bus error while execute make -jN (N>1)
Substitute m4 obsolete macros
Fix memory leak
[build] add cmake build system

 - add missing includedir for cmake
 - remove shared library version
 - python support
Resolve pidfile resource leaks

This patch resolves resource leaks caused by not closing the file streams upon
an write error.
[lib] removal of unused code
[build] fix the missing inclusion of config.h
[lib] add support for BSDs
elimate whites
[lib] add ccnet_daemonize
cleanup some code