[GIS.lab] prepare version 0.6: merge dhpc-service-dev into master

[Martin Landa]

Hi,

I would like to merge `dhcp-service-dev` branch which solves DHCP
service updates reported as #505 [1] into master. After that a new
branch for version 0.6 could be created. This version will be still
based on Ubuntu 12.04LTS but able to operate with third party DHCP
servers.

What do you think? Thanks, Martin

[1] https://github.com/gislab-npo/gislab/issues/505

-- 
Martin Landa
http://geo.fsv.cvut.cz/gwiki/Landa
http://gismentors.cz/mentors/landa