ikiwiki hosting internals/ todo/ htaccess support

.htaccess files are currently ignored. Would be nice to allow users to include them in their source, and use them.

On the ikiwiki side, that is just a matter of configuring `includes` to make it not skip .htaccess files.

On the apache side, config has to include 'AllowOverride All'. Also 'Options SymLinksIfOwnerMatch' is needed to use the RewriteEngine from htaccess files.

Apache's htaccess documentation explains the overhead that searching for and using htaccess files entails.

We'd need to look at the security of it and make sure .htaccess files cannot do anything bad.

A final reason not to do it, btw, is that it locks us into using apache.

done -- see apacheinclude.