Build on debian sid

[v4hn]

As a side-show. The non-rosdebian packages (i.e. natives in /usr) should be preferred there.

[v4hn]

Work in Progress is going on here.

The main issues identified so far are:

• missing rosdep entries for unspecified debian distributions (e.g., libfltk-dev, log4cxx)
• stricter compiler errors regarding missing includes of standard headers (e.g., in eml)