Simplify make install space and package build

[asmodehn]

The main simplification planned for 0.2 is to not build the install space any longer (tricky to manage + extra maintenance) but instead rely on rosdep to install the package from pip. see #18.

[asmodehn]

While this would be nice, it is not an option in company like yujinrobot
The development workflow consist in distributing the install space around.

So we still need to support the install space creation somehow...

[asmodehn]

After some discussion, it seems that yujinrobot is not interested in supporting "usual python workflow" and "latest is best" policy.
Instead the focus is on "stable (whatever is in base system, ie ubuntu debs) is best" and "usual ros workflow".

For any software project we should provide tools that strives to reduce the differences in code required by all final users (to make source code maintenance easier).

As catkin_pip is concerned, it means that we want to be able to have catkin_pip triggering usual catkin workflow in some cases (ROS workflow + ROS pkg build), and python workflow (+pip package) in others.

We need to develop such a system, so that packages using catkin pip can switch behavior easily.
Ex : the presence of a package.xml could be a good trigger to chose usual catkin workflow over python workflow

This would solve our package creation problem , since we wouldn't need to support deb creation from pip packages, or tricky dependencies. We would have either :

• catkin_pip -> catkin -> rosdep -> debs
• catkin_pip -> python -> pip

[asmodehn]

#61 seems to solve this issue in a decent way...