Git.pm: Use stream-like writing in cat_blob()
This commit fixes the issue with the handling of large files causing an
'Out of memory' perl exception. Instead of reading and writing the whole
blob at once now the blob is written in small pieces.
The problem was raised and discussed in this mail to the msysGit mailing
list: http://thread.gmane.org/gmane.comp.version-control.msysgit/12080
Signed-off-by: Gregor Uhlenheuer <kongo2002@googlemail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>