Added Debian specific configuration to the init script

Closes #205
Closes #204
Added a "elasticsearch::customize" attribute file to customize the cookbook's default attributes

Closes #208

Related: #112, #168, #178, #179, #180, #196, #208
[FIX] Changed, that Chef doesn't change the owner of `pid_path` to the Elasticsearch user

Since a95a3f7, the default `pid_path` attribute is "/usr/local/var/run".

However, the default recipe define this as directory resource and
specify that user/group owners are `elasticsearch`, which clashes with
other services running potentially on the system.

This directory should belongs to root and allow elasticsearch to write its pid.

A `chown` call is added into the init script.

Closes #193
Closes #194

Related: #108
Merge branch 'master' of github.com:elasticsearch/cookbook-elasticsearch