bunsan_use_pkgconfig() implementation.
bunsan_use_python_libs() implementation.

bunsan_use_python_libs()
bunsan_use_python1_libs()
bunsan_use_python2_libs()
bunsan_use_python3_libs()
bunsan_use_python_libs_minimum()
bunsan_use_python1_libs_minimum()
bunsan_use_python2_libs_minimum()
bunsan_use_python3_libs_minimum()
bunsan_install_python_module() implementation.
bunsan_install_python_module() -> bunsan_install_python_module_target().
bunsan_install_python_module_common() refactoring.
bunsan_install_python_module_init() implementation.
RPATH fix.
bunsan_install_python_module_common() fix.

Installation to ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}.
bunsan_install_python_module_common() fix.

LIBDIR became lib.
INSTALL_RPATH support.
Merge branch 'master' into yandex_rhel5