storageFormats: Correct small things and cosmetics.

Correct several small errors, fix some printouts and move some printing code
from printMetadata to the eventMetadata's print method, which makes more sense.
pyInterface: Propagate class rename to python.

Propagate the renaming of the eventFileWriter class (formerly the
dataFileWriter) to the python version of the class and change the only script
using it accordingly.
utilities: Add function returning git hash.

Add a new function to the reportingUtilsEnvironment collection which just
returns a string with the current git hash. Also change the function printing
the git hash information so that it uses the newly introduced function instead
of the preprocessor variable.
storageFormats: Add std::complex to the hashCalculator.

Add the possibility to update the hash in the hashCalculator with values of
type std::complex<double>.
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.