Adding documentation around folder structure for packages
Fixed failing comparison due to folder separators
[#51148043] Added precise debian pkg metadata for elasticsearch
[#51148043] Added copyright data for debian pkging
[#51148043] Overriding dh_install for missing files & dirs

We have to introduce override_dh_install as it was failing to
automatically install packages from bin, lib, and config folder with the
default procedure for dh_intsall.

For more information on dh_intsall refer:
[here](http://manpages.ubuntu.com/manpages/precise/man1/dh_install.1.html)
[#51148043] Adding textfile & txt files for pkging
[#51148043] Fixing bin folder copy error for es pkg
[#51148043] Adding missing pkg dependency for ex pkg
[#51148043] Fixed the libsigar error for es pkg

Following error was thrown when the file was not copied over to
/usr/share/elasticsearch/lib/sigar folder.
   no libsigar-amd64-linux.so in java.library.path
[#51148043] Added inital pkg for lucid for elasticsearch
[#51148043] Added information about the rules in doc
[#51148043] Choose sigar file as per system arch

If lib-sigar-<arch>-<system>.so that is copied over for deb pkg isnt
correct then results in build failure (even if all .so files are
copied). To fix this we are now using the DEB_BUILD_ARCH to get the
correct architecture.
[#51148043] Pulled {post/pre}{inst/rm} steps from upstream for es
Merge pull request #3 from alphagov/elasticsearch_pkging

[#51148043] elasticsearch 0.20.6 deb pkg for precise and lucid