Use "member" to refer to struct members as that's the term used
by the C standard.
Use lzma_options_delta.dist and such in docs so that in Doxygen's
HTML output they will link to the doc of the struct member.
Clean up a few trailing white spaces too.
broken. API has changed a lot and it will still change a
little more here and there. The command line tool doesn't
have all the required changes to reflect the API changes, so
it's easy to get "internal error" or trigger assertions.
