Documentation: Clarify etcd security documentation

Signed-off-by: Vincent Ambo <vincent@kivra.com>
docs: fix documentation for HTTP read/write timeouts

The documentation for these options has been incorrect ever since their
addition via commit 084dcb55. This broke upgrading a CoreOS stable
cluster to 410.0.0 because the user was using the example TOML config
which contains:

    http_write_timeout = 10

This was silently ignored in the old stable version which predates the
addition of these options. After upgrading etcd began failing with:

    Type mismatch for 'config.Config.http_write_timeout': Expected float
    but found 'int64’.

Original issue: https://github.com/coreos/update_engine/issues/45
etcdserver: add default peer
raft: init prev: vote for none
raft: fix node test
Merge pull request #990 from coreos/fix_node_test

Fix node test
build: add build script and update readme
Merge pull request #991 from jonboulle/master

build: add build script and update readme
Revert "build: add build script and update readme"

This reverts commit 2866a7488ee2eb489405cd50a906e43f24044d8c.
raft: fix ignore term
Merge pull request #989 from coreos/fix_ignore_term

raft: fix ignore term
Merge pull request #983 from marineam/doc

docs: fix documentation for HTTP read/write timeouts
.: explain the LGTM protocol
.: add MAINTAINERS file
etcdserver: change default id to 0x1
Merge pull request #988 from coreos/default_peers

etcdserver: add default peer
doc: update build instructions in README
Merge pull request #995 from jonboulle/master

doc: update build instructions in README
*: add wal
main: use data-dir as the path to data directory flag