Integrate loupe with debhelper

[vladandrew]

We use two tools from the debhelper suite:

• dpkg-buildpackage to automatically build a debian package
• dh_auto_test to run the test suite for a package

We also use apt-get source to download the sources of a given debian package.

We build two wrapper over this scripts: debhelper_build.sh and debhelper_test.sh.

This pull requests adds a generic loupe docker image: Dockerfile.debhelper. This image receives as an input the name of the target app and automatically downloads the sources, builds the target and then runs loupe analysis on the test suite.

[olivierpierre]

Thanks @vladandrew , it looks good and it is also non-intrusive so I'll merge it right away :)

I see your point about instrumentating all executables produced by the build process -- that'll be ideal indeed. They are pretty easy to identify after the build process with a find command, however the main issue is that loupe does not support more than one binary to instrument for now. I'll create an issue for that.