correct version number for 8.18 release

bump version for release

prepare for release

Merge branch 'tmp-master' of https://github.com/jite/rsyslog-doc into…

… tmp

Merge branch 'master' into v8-stable

Conflicts:
	source/conf.py

Merge pull request rsyslog#162 from teifler/ompipe2doc

Added ompipe to doc

imfile: document new parameter

Merge branch 'master' into v8-stable

Merge branch 'master' into v8-stable

Conflicts:
	source/conf.py