Added (empty) class BaseH5Recorders.
Started to work on BaseH5Recorder.
Fixed missing initialisation and a couple of bugs in H5Recorder.
Completed BaseH5Recorder with general code and left specific code only
in H5Recorder.
Added interface and base structure of TriggeredH5Recorder.
Added also an XML configuration file for testing purposes.
Improved the way in which an unlimited dataset is allocated.
Completed TriggeredH5Recorder.
Completed TriggeredH5Recorder and improved the example configuration
file.
Added code for SHA-1 digest computation and relative method in
BaseH5Recorder.
Added filename() method to BaseH5Recorder.
Revert "Added filename() method to BaseH5Recorder."

This reverts commit 53ba5ba4152d20b5061f85e026710b5ac9c2404e.
Revert "Added code for SHA-1 digest computation and relative method in"

This reverts commit 17716dbded28dda0a7aa3d2ed4095e875ede353d.
Added filename() method to BaseH5Recorder.
Merge branch 'recorders': finished work on H5 recorders, which can now
be incorporated into the master branch.