add multiple path support to go plugin

plugins/available/go.plugin.bash

@@ -5,7 +5,18 @@ about-plugin 'go environment variables & path configuration'
 
 [ ! command -v go &>/dev/null ] && return
 
+function _split_path_reverse() {
+  local r=
+  for p in ${@//:/ } ; do
+    r="$p $r"
+  done
+  echo "$r"
+}
+
 export GOROOT=${GOROOT:-$(go env GOROOT)}
 pathmunge "${GOROOT}/bin"
+
 export GOPATH=${GOPATH:-$(go env GOPATH)}
-pathmunge "${GOPATH}/bin"
+for p in $( _split_path_reverse ${GOPATH} ) ; do
+  pathmunge "${p}/bin"
+done