Upgrade to LibreOfficeKit as per LO 4.3.
Support both liblibreoffice and LibreOfficeKit
Update README and comments for LibreOfficeKit changes
Note that options require LibreOffice >= 4.3.0 in --help message
Exit with EX_USAGE if command line arguments invalid
Say which hook function we failed to find
Explicitly note that 4.3.0rc1 is needed for specifying options