Doc updates to sphinxsearch on Google Code

Changed Paths:
    Modify    /trunk/doc/sphinx.xml

moved sphinxql reference to a separate doc chapter

Changed Paths:
    Modify    /trunk/doc/sphinx.xml
    Modify    /trunk/sphinx.conf.in
    Modify    /trunk/src/searchd.cpp
    Modify    /trunk/src/sphinxrt.cpp
    Modify    /trunk/src/sphinxutils.cpp

updated docs; renamed binlog_max_log_size and made it 128M by default; disabled subtree cache by default