Updated build.sh to properly reset the current branch while building documentation.
remove leftover ABNF description from initial RainerScript idea

Long replaced left-over from the initial design phase years ago.
rainerscript: remove old cruft
Merge branch 'v5-stable' of github.com:rsyslog/rsyslog-doc into v5-stable
Merge branch 'v5-stable' of github.com:rsyslog/rsyslog-doc into v5-stable
Merge pull request #41 from rgerhards/v7-stable-rainerscript

V7 stable rainerscript
Merge branch 'v5-stable' into v7-stable
Merge branch 'v7-stable' of github.com:rsyslog/rsyslog-doc into v7-stable
Merge branch 'v7-stable' into v8-stable
Merge branch 'v8-stable' of github.com:rsyslog/rsyslog-doc into v8-stable