Scheduler: optimization when timing out connections

This patch adds a good improvement on performance when the event poll
system start checking for candidates to timed out connections. It adds
two main lists:

  - sched->status_queue: Open socket connections list that have not sent any data
  - cs_incomplete: Client requests list that still have some pending data

When the timer triggers the timeout check, now the Scheduler will look
over those two global lists at thread level, avoiding to check connections
that are in a good state.

This performance improvement is faced when having several active connections
in the server.

Signed-off-by: Eduardo Silva <eduardo@monkey.io>

Conflicts:
	src/mk_request.c
Scheduler: Close connection after MK_PLUGIN_STAGE_10

Signed-off-by: Vladimir Cernov <gg.kaspersky@gmail.com>

Conflicts:
	src/mk_scheduler.c
Virtual Host: validate dummy files (Fix #155)

Signed-off-by: Eduardo Silva <eduardo@monkey.io>
Scheduler: on timeout, validate incomplete linked list (#163)

Signed-off-by: Eduardo Silva <eduardo@monkey.io>
Request: unlink request node from cs->request_lists

Signed-off-by: Eduardo Silva <eduardo@monkey.io>
Kernel: support Debian version format

Signed-off-by: Eduardo Silva <eduardo@monkey.io>
Header: when using Chunked encoding, do not set Content-Length

Signed-off-by: Eduardo Silva <eduardo@monkey.io>
Utils: use memcpy() on URL decode

Signed-off-by: Eduardo Silva <eduardo@monkey.io>
Configure: bump to v1.5.4

Signed-off-by: Eduardo Silva <eduardo@monkey.io>
Debian: bump to v1.5.4

Signed-off-by: Eduardo Silva <eduardo@monkey.io>
Doc: Update ChangeLog for v1.5.4

Signed-off-by: Eduardo Silva <eduardo@monkey.io>