[Pmwiki-mode] TikZ and beamer

[Lukasz S. <luk...@gm...>]

I have added mumamo chunkers for tikz and beamer, and I'm working on
previewing for tikz. preview-latex still doesn't work for tikz yet,
but as a by-product I wrote a function viewing the tikz block in
outside viewer. `pmwiki-view-tikz' Works also without mumamo.