Add message queue trigger support (#218)

Adds support for message queue triggers based on the NATS-Streaming message queue.

This lets the user map a queue topic to a function, and optionally send the function's response into another queue topic.

The message queue trigger manager is designed to be message queue independent, so we should be able add support for more queues by adding implementations for the relatively simple mqtrigger.MessageQueue interface.

hack/release.sh

@@ -93,6 +93,7 @@ build_yaml() {
     cat fission-logger.yaml | sed "s#fission/fission-bundle#$tag#g" > $outdir/fission-logger.yaml
     cat fission-openshift.yaml | sed "s#fission/fission-bundle#$tag#g" > $outdir/fission-openshift.yaml
     cat fission-rbac.yaml | sed "s#fission/fission-bundle#$tag#g" > $outdir/fission-rbac.yaml
+    cat fission-nats.yaml | sed "s#fission/fission-bundle#$tag#g" > $outdir/fission-nats.yaml
 
     cp fission-nodeport.yaml $outdir
     cp fission-cloud.yaml    $outdir
@@ -138,7 +139,6 @@ make_github_release() {
 	   --tag $gittag \
 	   --name "Nightly release for $(date +%Y-%b-%d)" \
 	   --description "Nightly release for $(date +%Y-%b-%d)" \
-	   --pre-release	   
 
     # attach files
 
@@ -165,7 +165,7 @@ make_github_release() {
 	   --file $BUILDDIR/cli/windows/fission.exe
 
     # yamls
-    yaml_files="fission.yaml fission-logger.yaml fission-rbac.yaml fission-openshift.yaml fission-nodeport.yaml fission-cloud.yaml"
+    yaml_files="fission.yaml fission-logger.yaml fission-rbac.yaml fission-openshift.yaml fission-nodeport.yaml fission-cloud.yaml fission-nats.yaml"
     for f in $yaml_files
     do
 	gothub upload \