storageFormats: Add ampitudeMetadata classes.

Add the amplitudeMetadata and the amplitudeFileWriter classes to the
storageFormats subdirectory. Adapt the printMetadata executable accordingly and
add the amplitudeMetadata to the linkDef header.
amplitude: Add waveDescription constructor.

Add a new constructor to the waveDescription class which allows to build it
from an amplitudeMetadata object, which should facilitate the reading of
amplitude files.
pyInterface: Add bindings for amplitudeMetadata.

Add bindings for the amplitudeMetadata and amplitudeFileWriter classes. They
only have been tested rudimentarily and should be checked more thoroughly.
pyInterface: Move initialization of printing counter.

Initialize the printing counter and the printing classes in the printingUtils
submodule instead of at the beginning of every script. This seems to work,
however, somehow there seem to be troubles with the silencer class. As the
whole package is in the process of being rewritten, the details will be ironed
out once the new version is more or less stable.
storageFormats: Fix convertEventFile.py.

Fix the convertEventFile.py script which seems to have been broken since a few
commits ago because of an interface change in the eventFileWriter.
storageFormats: Add events type to eventMetadata.

Add the possibility to save the type of events (e.g. "generated" or "real") in
the eventMetadata object so that they can be uniquely identified afterwards.
This is necessary so that this information does not have to be carried in the
file name or location.