Support for extracting .tar.xz files.

Since the current makegyp adopt Python 2.7. It requires an additional pyliblzma library to support xz files. See http://goo.gl/tPxfTR for more information.

Signed-off-by: Olli Wang <olliwang@ollix.com>
Adds boost as dependency for yamlcpp.

Signed-off-by: Olli Wang <olliwang@ollix.com>