Allow plugins to create view types

Closes #904

cmd/micro/micro.go

@@ -403,6 +403,7 @@ func main() {
 	L.SetGlobal("Reload", luar.New(L, LoadAll))
 	L.SetGlobal("ByteOffset", luar.New(L, ByteOffset))
 	L.SetGlobal("ToCharPos", luar.New(L, ToCharPos))
+	L.SetGlobal("NewViewType", luar.New(L, NewViewType))
 
 	// Used for asynchronous jobs
 	L.SetGlobal("JobStart", luar.New(L, JobStart))

cmd/micro/view.go

@@ -18,6 +18,11 @@ type ViewType struct {
 	scratch  bool // The file cannot be saved
 }
 
+// NewViewType creates a new ViewType - useful for plugins
+func NewViewType(kind int, readonly, scratch bool) ViewType {
+	return ViewType{kind, readonly, scratch}
+}
+
 var (
 	vtDefault = ViewType{0, false, false}
 	vtHelp    = ViewType{1, true, true}