Fix the build for Fred build 1451.

Required by breaking changes in Fred:
* 1f56cca52c7b3af68dd606138b8796ce5e37bdff adds an argument about
public gateway mode without backwards compatibility. At this level, it
may be necessary to bind to different ports or use a different
FreenetWrapper instance depending on the request source IP. For the sake
of fixing the build, hardcoding is sufficient.
* a3a42761df0792f3e1ed2bc586e6cf416893fa7a renames MIMEType to
FilterMIMEType.
* a25a12982d0b479517f089f898aab6b709226eba adds an argument to ignore
hidden files without backwards compatibility. As FProxy ignores
hidden files, it is consistent for Winterface to do the same.
* af05b789ced3eac2d1e2959b4049192e62f66a18 adds an argument to encode
SimpleFieldSet values in base64 without backwards compatibility. Enable
it when adding a darknet node in order to be more permissive about
noderef formatting.
* 8da663c93b942c0649043d7daffa43f07ee56091 removes access to identity,
and uses public key hash instead. Identity is sometimes the same as the
public key hash (02167819d230733267afd49f9db1100fc4a4d30e), but:
(2013-8-18 11:03:17 EST) @toad_ | identity will go away completely when
negtype9 is mandatory
* ae690f63af14ee0c4343f78897c0385caaea2496 removes recommended
freenet-ext version constants. Remove the feature Winterface used it in,
as the recommended freenet-ext version seems like something the updater
should handle.