Added a new test called output_ketama_weighted_keys. It prints the hashing result

Added a new test called output_ketama_weighted_keys. It prints the hashing result
for hashing keys 0-9999 and outputs a file called ketama_keys.test.

We can then use this file to test ketama hashing in other libraries like spymemcached.
With a new class I just checked in called KetamaKeysTest (must download source from github).

javac -cp target/classes src/test/manual/net/spy/memcached/test/KetamaKeysTest.java
java -cp target/test/classes:target/classes:src/test/manual net.spy.memcached.test.KetamaKeysTest > ketama_keys.txt

To test the ketama hashing is working the same for both libraries, I ran this command:

$ cmp ketama_keys.txt /sandbox/b-server-3-4/srcroot/svr/import/common/java/java-memcached-client/ketama_keys.txt