Move liblibreoffice into LibreOfficeKit.

Change-Id: Ib2754a77be470faaa6f9b27644a1d8dd082ed2b8
Rename C api of LibreOfficeKit.

However for the sake of ABI compatibility we can't change
liblibreoffice_hook.

Change-Id: I0e921efeeab40ef1b53a67c0e7a89d4c75ced831
Upgrade LibreOfficeKit C++ API.

Change-Id: If263b8fc748f67a1ed423c0f3f7cd465cf533993