maps: make sure AuthorMaps don't overwrite themselves, fix overriding Author maps for the Python repo got truncated because of the author map stupidly writing upon itself. This patch implements a better and faster scenario, where entries will only be written to the saved author map if they're not coming from that file. They're also now streamed into the file directly, instead of having to re-open the file on every entry, and formatting is preserved.

#!/bin/sh
mkdir temp || exit 1
cd temp
svnadmin create repo
svn co file://`pwd`/repo wc
pushd wc
mkdir -p project/trunk
svn add project
svn ci -m 'trunk'
cd project/trunk
echo a > a
mkdir narf
svn add a narf
svn ci -m 'file and empty dir'
popd
svnadmin dump repo > ../empty_dir_in_trunk_not_repo_root.svndump
echo 'dump in empty_dir_in_trunk_not_repo_root.svndump'
echo 'you can probably delete temp now'