[sugar] How to handle application protocols

[J.M. Maurer]

> Alternatively, things could work as today (rpms for libabiword and
> libabiword-plugins), but bundles can provide their own plugins that can
> override the system-wide plugins?
> 
> Is this feasible?

The only thing needed is to be able to specify a plugin search path.
Right now we look only in ~/.AbiSuite/plugins and
[libdir]/abiword-2.6/plugins.

That way we could ship plugins in the bundle as well, overriding the
system-wide plugins.

We would need to be really careful though, as plugins are C++ plugins at
the moment. There is no stable api at the moment. However, we do try
really hard not to break plugins during a stable series; this is not set
in stone though.

Marc