to support updates in Subfolders with Subversion > 1.8
Fix: Ignoring svn:externals on local Modification Check.
Add: Added Argument switch to alow skipping the svn switch call.
When a SVN repository has some svn:externals properties, files will be
reported with the X attribute, and lines will be added at the end to
list externals statuses with a text looking like
"Performing status on external item at ....".
Such lines were counted as a local modification by the regex, and the
module returned a change, even though they were none.
To have a clean (and parsable) "svn status" output, it is recommended
to use the --quiet option. The externals will only appear if they have
been modified. With this option on, it seems even safer to consider
there are local modifications when "svn status" outputs anything.
The default is changed from 'yes' to 'no' to follow
subversion behavior (ie, requiring explicit confirmation
to erase a existing repository). Since that was not working before
cf #370 and since the option was ignored before and unused, this
should be safe to change.
