added --with-libsylph configure option which enables the use of externallibsylph.
implemented Robinson-Fisher method to calculate combined probability.
add AC_CANONICAL_SYSTEM to configure.ac for target variable.
added --enable-windows to configure.
Add GDBM support.Add mode switch for standalone and libsylph app.
addes SQLite3 support.
check for QDBM on configure.
added built-in libsylph, and use it from textcontent-filter.c.