[Libreoffice] [GSoc] libvisio progress update

[Tibby Lickle]

A git repository has been set up for the Visio project and I've gotten
access rights to it - so for those of you wondering what the libvisio
folder is, it's this project.

We've gone with a heavily stream-based approach. Internal VSD streams
are decompressed and are seekable and readable. For this, libwpd has
been used as a base (WPXInputStream) as well as a source of utility
functions (e.g. converting bytes to uints) that work with
WPXInputStreams.

Right now, the project is successfully reading the trailer (this is
the compressed list of pointers to the other streams in the doc) and
getting the stream pointers. "Success" is currently defined by manual
comparison with what OleToy shows. The next step is figuring out which
types of streams are useful and dealing with them appropriately.

Eilidh