Update README.md

Added a request that contributors don't create branches in this repository.
Changed request a demo link to be absolute, should fix #SITES-100
Merge pull request #142 from PaintScratcher/adamt-fixes

Changed request a demo link to be absolute, should fix #SITES-100
2.5: update to upgrading with xdcr.
nanoc.yaml: drop off dev guide version 1.8 from list of versions due to insufficient space (MB-11271)
default.erb: added try couchbase button to header
dev guide: fix typos (MB-10231)
Merge branch 'stage' of https://github.com/couchbaselabs/docs-ng into stage
Merge pull request #141 from mnunberg/stage

Libcouchbase 2.4-beta Docs
C SDK: add version 2.4 beta
update links to C v2.4 API reference
change include_doc to include_docs in multiple files and across releases in the AG.
add static files for 3.0 beta
Merge branch 'stage' of https://github.com/couchbaselabs/docs-ng into stage
Added a hack for the assets-dita CSS.
files for beta release
index.html: add 3.0 beta section
Removed reference cbbackup-incremental and cbbackup-merge-incremental. These tools appear not to exist yet.
Fix incorrect link to API docs in Node.js docs.
Merge pull request #145 from brett19/stage

Fix incorrect link to API docs in Node.js docs.