debuild doesn't fully use all cores when 'catkin build'

[marinagmoreira]

Without all cores being fully used debian build is really slow.

Current workaround for this is to:

1. start debuild for catkin configs
2. stop it when it starts compiling
3. do 'catkin clean' do delete previous debian build
4. do 'catkin build' (directly issuing a catkin build uses all available resources, which is much faster), wait for completion
5. re-run debuild to completion (it will use the previous build instead of doing everything from scratch)