debian/ubuntu packaging, v2

See #93, #121

Added

* package build rules to debian/

* install rules to makefiles

* guides on packaging and deb-repository creation

Several files in /debian directory still contain stub info (READMEs for the most part). Some meaningful content can be added there or those files can be safely removed for the next release.

In /src/doc/packaging.md doc mentioned current forks for libraries packaged. We probably need to push those somewhere and update document accordingly. Any suggestions here?

And, btw, one already can install snabbswitch using apt:
```
wget -q http://test.snabb.logiceditor.com/key.asc -O- | sudo apt-key add -
echo "deb http://test.snabb.logiceditor.com trusty free" | \
  sudo tee -a /etc/apt/sources.list.d/test.snabb.logiceditor.com.list
sudo apt-get update
sudo apt-get install snabbswitch
```
May be it will be a good idea to save this info somewhere in repository documentation or someplace else?