[kde-edu]: KAlgebra plasmoid

[Aleix]

Hello kdeedu!
Last days I have been working on KAlgebra (as I told on my blog),
mainly on the core, but to distract from it a little, I have been
working on a little calculator plasmoid using KAlgebra, which is quite
nice.

Don't look for it on the svn repo, it is not yet there, because I
don't really know where to put it. I'm working with it at
kdeedu/kalgebra/src/plasmoid, because it works well for me. I've added
a conditional compilation feature so that there is no forced
dependency to KDEBase, but I'd like you to agree with my decision,
because maybe someone would prefer something like a kdeedu/plasmoids
directory or something like that, I don't really know, but I'd like it
to be in KDE-Edu, because i am linking against some KAlgebra libraries
and it makes all much simpler.

If I don't receive any objection, I'll commit it inside kalgebra
directory (the first path I pointed out).

Bye!
Aleix