imtcp: fix busy-loop in the tcp listener

This patch fixes the high CPU usage when rsyslog
run out of FDs

reference
http://lists.adiscon.net/pipermail/rsyslog/2013-October/034488.html

Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>
Signed-off-by: Susant Sahani <susant@redhat.com>
maintain ChangeLog
bugfix: make dist failed due to removed header file

this was forgotten to remove from the makefile
bugfix: README.md was missing in release tarball

closes: https://github.com/rsyslog/rsyslog/issues/91
Merge branch 'v7-stable' into v8-stable