Changed indent from tab to 4 spaces
Added pyddww like variables.

In order to adapt the pyddww style the variables shotnumber, edition,
experiment and diagnostic were added. The corresponding underscored
varialbes __shotnumber, __edition are still included until all functions
are adapted to the new style.
Rewrote get_B to getMagneticField

get_B was renamed into getMagneticField. It now returns a magneticField
object containing the information of about the magnetic field. The
magneticField class is derived from object but __getitem__ and keys have
been implemented to be compatible to the previously used dict.