Mathed patch

[Alejandro Aguilar Sierra]

Hello All,

I have commited several bug fixes for *some* of the mathed bugs recently
reported. Sorry for the "weak breeze" but I really don't have all the time
I'd like. Anyway I'll try to fix most reported bugs before 1.0.1 release.

The only new stuff is the root (somebody insisted I had to add it, now
test it!). To insert it just call "math-insert root".

I need to get some extra energies (and time) in order to participate in
the writer's discussion.  ;) 

Enjoy!

Alejandro