ESource: Implement the GProxyResolver interface.
ESource: Implement the GProxyResolver interface.

An ESource with an ESourceProxy extension can now serve as a
GProxyResolver.  Calling g_proxy_resolver_is_supported() on an
ESource will reflect this constraint.  Attempting a proxy lookup
operation on an ESource for which g_proxy_resolver_is_supported()
returns FALSE will fail with G_IO_ERROR_NOT_SUPPORTED.

tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server