Don't use click's newline echoing

click.echo does two write calls, which get flushed immediately. Using
this in multiprocessing might make output overlap. Using a single
write-call apparently resolves that issue, although i don't know why.

A proper solution would be to use locks, but e.g. multiprocessing's
logger doesn't seem have nearly as much flexibility as others. For now
it seems to be bugfree enough.

vdirsyncer/log.py

@@ -32,7 +32,7 @@ class ColorFormatter(logging.Formatter):
 
 class ClickStream(object):
     def write(self, string):
-        click.echo(string.rstrip())
+        click.echo(string, nl=False)
 
 
 stdout_handler = logging.StreamHandler(ClickStream())