@jlporter "making InitiatePropertyCacheLookup static"

Now that you mention it, it's actually kind of weird that this is in proxy_interface at all.  I think it makes more sense as a static method in proxy_fetch.

For now I'd like to put this change in so that we work with ProxyInterface as of 1.5.27.3 and also make a separate internal change so that the next release of PSOL won't require us to instantiate a ProxyInterface here.  Is that ok?