Merge pull request #113 from squaremo/gh-pages

Move documentation to gh-pages site

Addresses part of issue #86.
mention tcpdump/wireshark debugging

Closes #118.
we don't want to pull down all weave image, just latest
Merge branch '119_document_vagrant_build' of https://github.com/squaremo/weave into squaremo-119_document_vagrant_build
cosmetic
Elaborated on vagrant instructions

It made different assumptions to the "regular" instructions (namely,
that the reader already had a working directory).