btk::AcquisitionFileWriter modifies the input when you write it in a C3D File

What steps will reproduce the problem?
1. Read a TRC file
2. Write it as a C3D file 
3. The timestamp of the input is modified and their metadata are modified.

What is the expected output? What do you see instead?
No input modification. Instead, it is possible that the input is
reprocessed by its parent and then modify the pipeline another time ...

Please use labels and text to provide additional information.
From the C++ code source of btkC3DFileIO.cpp [1], it is recommended to
create clones of the metadata and other objects instead to modify them
directly in the input.

[1]
http://code.google.com/p/b-tk/source/browse/BTK/trunk/Code/IO/btkC3DFileIO.cpp

Original issue reported on code.google.com by arnaud.barre on 27 Jan 2010 at 5:44

mollynnobrien / b-tk

btk::AcquisitionFileWriter modifies the input when you write it in a C3D File #3