Cache Settings in SvnUtil

SvnUtil.getSettings recreates the Settings every time it is called. Attached is a simple patch to cache the Settings.

The current behavior is ugly for a couple of reasons. One, the settings cannot be easily adjusted at runtime, this has no effect on the provider:

SvnUtil.getSettings().setUseNonInteractive(false);

Second, the way this class is used has terrible performance implications. SvnCommandLineUtils calls it over and over. If the settings file is present, it will be re-parsed numerous times during the execution of a single SVN command.

A similar patch should probably be applied to the GIT and CVS providers, which appear to have copied the SvnUtil code. SCM-522