README: Updated README.

Removed module references which are transferred to syslog-ng upstream,
and updated syslog-ng version requirement.
kafka: Use correct stats header file
configure: turn on silent rules if it is possible

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>
java-dest: add java files to the list of extra dists

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>
java-dest: the classloader should be a specific per destination,

but it should use the same ClassLoader for loading all the classes,
else the objects can't use each other.

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>
java-dest: use name-value pair as string in option instead of previous option,

because with this solution won't run into error in case of reserved word.
e.g.: options(key(value)) config parsing error, because key and value are both
reserved words.

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>
java-dest: elasticsearch example updated for the new interface

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>