Debian/Ubuntu Packages Close #70

I know it's a **1.2** feature, but do not slap me *'cause it's Christmas time - wohooooooo*.

Features tested and working on `make package`:
- works with *mpich2* and *openmpi*
- works with **serial libSplash** too and with/without `TOOLS_MPI`
- supports **-dbg** packages
- creates a meaningful package name (see e.g. hdf5 package names)
- adds all relevant meta information to `.deb` files (dependencies, suggestions, ...)
- is always a "dev" versions because it ships include headers too
- `.travis.yml` cleaned up (global vars now on a central place) and installs the `.deb` package for example compiles (tests still compiled in-source)

Things to be done / reviewed:
- [x] Can I add your ZIH E-Mail address in the code? (Yeah, they got a good spam filter.)
- [x] Maybe we ship only parallel packages with releases (as additional download).
- [x] Have to check if I call the *serial* package *libsplash-serial*. Does the Debian flag *enhances* ~~"upgrade and replace" that or~~ just "add" to it ~~?~~.
- [x] I would postpone `.rpm` and OSX shipping (I didn't find a good doc for the first and the API is still changing to heavily for OSX and I have no testing env for it) - and of course NSIS Windows shipping can *wait* due to missing relevance for HPC (but there are, like in OSX, users that do their data analysis on it) ...
- [x] install `splash2xdmf.py` python module [example](https://packages.debian.org/jessie/python-h5py), [policy](https://wiki.debian.org/Python/Packaging)