Initial commit for python interface

Created directory structure and files.
Started with basic class layout (without any functionality).
Initial commit for python interface

The python interface has been designed as a 'calculator'
of the Atomistic Simulation Environment.
For info on how to install the interface, see <root>/python/INSTALL.

This implementation is a first draft.
It writes an input file in the original format for the ljmd-*.x binary
and then calls the binary on this input file.

For later versions, we may consider to change the file format,
since the line-dependent syntax is very unflexible.
The code for the interface will, of course, have to be adapted
accordingly.
Forgot to delete the original directory layout
Added info on built-in ASE viewer

The ASE viewer allows to visualize Atoms objects
directly in python.
Renamed MyMD class to FileIOMyMD

The current python interface can just read and write input files.
This was easy to start with, since it does not rely on the internal
structure of the C++ code.
However, it is less powerful than directly exposing the internal
structure to python via the cython module and this is the intended next
step.
The calculator class interfacing to cython will be called MyMD and
derive from ase.calculators.Calculator, while the calculator class that
reads input/output files is called FileIOMyMD and derives from
ase.calculators.FileIOCalculator
Initial commit for cython interface

The cython interface will depend on the internal structure
of the MyMD C++ code. The development can thus only really
begin, once a properly compiling version of this code stands.
FileIOMyMD now stores frames.

The FileIOMyMD now has the capability to internally
store the frames of a MD run.
A frame can consist of atoms as well as further calculated
properties, such as temperature, potential energy etc.
Introduced scale factor for velocities

In ljmd.c, velocity units are such that v*dt has units angstroms,
so v has units 10**(5) m/s
In ASE, ase.units.kB is by default in eV/K.
Furthermore, ase.md.velocitydistribution calculates with masses in amu.
If you set force_temp=True, you end up with kB=1 and  amu=1,
so the units of V are sqrt(amu/kB) = 91.1837 m/s
So you have to divide ASE's velocities by 1096.687
or, since T\propto v**2, scale T by 8.31446714569e-7
Merge branch 'interface'

Merging the Python interface into the master, containing the
up-to-date C++ code.
Minor python code modifications will be necessary.