Minor updates post-review

The demo client isn't really fit for purpose, so stop encouraging people to use
it.

Add some syntax highlighting

- remove redundant "where's the spec" section: this would belong in "About
matrix", but it's already there.

- E2E is in beta rather than dev

Fix a couple of broken links

Move some bits of the README around. No words were changed in the making of
this commit.

this is rst so name it accordingly

Signed-off-by: Fabian Niepelt <fniepelt@takios.de>

A user on #matrix:matrix.org was confused by the phrasing of the first
sentence in the paragraph and couldn't tell whether it was saying that
the homeserver stored the data or the clients did. This change splits it
into two sentences to make the subject of each sentence clear.

Replace the bash/perl gen_password script with a python one, and write a note
on how to use it.

Signed-off-by: Florent VIOLLEAU <floviolleau@gmail.com>

Add FreeBSD installation instructions for both Ports and Packages now that matrix-synapse has landed [1] in the tree.

[1] https://svnweb.freebsd.org/changeset/ports/405527

When installing synapse since all its dependencies are on PyPI

various fixes - thanks to Mark White for pointing out you need to run synapse before you try to register a new user

Added libffi-devel in CentOS 7 installation requirements and fixed indentation of yum groupinstall. Signed-off-by: Mads Robin Christensen <mads@v42.dk>

Signed-off-by: Mads Robin Christensen <mads@v42.dk>