New fully automatic machine translation for languages

PD's Language Editor is the kind of thing I would like to spend more
time on, but it's just not a priority compared to the myriad of key
program features that need implementing.

That said, I have finally added an automatic machine translation button,
which at least lets me to create basic support for missing popular
languages (Spanish and Portuguese at present).  While nowhere near as
good as human translation (obviously), it's at least *something*, and
hopefully it will attract some users who can help clean up the
translation.

(I've recently discovered that many other photo editors rely on machine
translation, e.g.
http://blog.getpaint.net/2011/04/17/paint-net-in-24-more-languages-tldr-yes/,
so I'm not alone in this.)

It takes a long time to translate all ~2000 phrases in the program
(several minutes), so I don't recommend using the button until
absolutely ready.
Fix resize UC to work with translations
Update Master language file

Last one for 6.2...?  Maybe...?
Update human-translated languages against new Master XML

Still need to send these off to translators, but at least they are
up-to-date against the 6.2 beta text.
New official Spanish translation

Machine translation only, thank you Google Translate!
New official Portuguese translation

Machine translation only, thank you Google Translate!