BUG/MINOR: acl: parser must also stop at comma on ACL-only keywords

Igor at owind reported that "url_reg,lower" does not parse because
find_acl_kw() looks for the parenthesis but not for the comma.
MEDIUM: stream-int: implement a very simplistic idle connection manager

Idle connections are not monitored right now. So if a server closes after
a response without advertising it, it won't be detected until a next
request wants to use the connection. This is a bit problematic because
it unnecessarily maintains file descriptors and sockets in an idle
state.

This patch implements a very simple idle connection manager for the stream
interface. It presents itself as an I/O callback. The HTTP engine enables
it when it recycles a connection. If a close or an error is detected on the
underlying socket, it tries to drain as much data as possible from the socket,
detect the close and responds with a close as well, then detaches from the
stream interface.
DOC: update the ROADMAP file

I already forgot to update it for dev20.
[RELEASE] Released version 1.5-dev21

Released version 1.5-dev21 with the following main changes :
    - MINOR: stats: don't use a monospace font to report numbers
    - MINOR: session: remove debugging code
    - BUG/MAJOR: patterns: fix double free caused by loading strings from files
    - MEDIUM: http: make option http_proxy automatically rewrite the URL
    - BUG/MEDIUM: http: cook_cnt() forgets to set its output type
    - BUG/MINOR: stats: correctly report throttle rate of low weight servers
    - BUG/MEDIUM: checks: servers must not start in slowstart mode
    - BUG/MINOR: acl: parser must also stop at comma on ACL-only keywords
    - MEDIUM: stream-int: implement a very simplistic idle connection manager
    - DOC: update the ROADMAP file
BUILD: last release inadvertently prepended a "+" in front of the date

No impact.
BUG/MEDIUM: stream-int: fix the keep-alive idle connection handler

Commit 2737562 (MEDIUM: stream-int: implement a very simplistic idle
connection manager) implemented an idle connection handler. In the
case where all data is drained from the server, it fails to disable
polling, resulting in a busy spinning loop.

Thanks to Sander Klein and Guillaume Castagnino for reporting this bug.

No backport is needed.
Merge branch 'master' of http://git.1wt.eu/git/haproxy