Add php-memcached extension

[anhlt]

I have added 2 packages : libmemcached and phpmemcached.
It work well. But have 2 problem:

• I have to add extension=/home/action/.parts/packages/php5/5.5.8-nitrous2/lib/extensions/no-debug-zts-20121212/memcached.so to file php.ini by hand.
• after compile php-memcached. autoparts raise error like this:
  parts: ERROR: No such file or directory - /home/action/.parts/packages/phpmemcached/2.1.0
  Sorry but ignore my modification in mysql.rb

[rgbkrk]

It would be really cool if you added libmemcached-dev and libmemcache-dev. I need it to build pylibmc. 😃