Add support for opening without filename arg

This allows the user to open notepad_squared without needing to pass a
filename as an argument, however, we currently don't support saving
files that have been opened in this manor

main.odin

@@ -16,11 +16,6 @@ main :: proc() {
 
 	args := os.args[1:]
 
-	if len(args) == 0 {
-		fmt.println("Usage: gui_cat <file1> [file2] [file3] ...")
-		return
-	}
-
 	config, ok := parse_config("config.ini")
 	if !ok {
 		log.fatal("failed to parse config file")
@@ -55,8 +50,12 @@ main :: proc() {
 	load_fonts(&app)
 
 	// Load files from command line arguments
-	for filename in args {
-		load_file(&app, filename)
+	if len(args) > 1 {
+		for filename in args {
+			load_file(&app, filename)
+		}
+	} else {
+		load_file(&app)
 	}
 
 	if len(app.files) == 0 {
@@ -91,20 +90,32 @@ load_fonts :: proc(app: ^App) {
 	app.line_height = app.fonts[app.current_font_index].size + 4
 }
 
-load_file :: proc(app: ^App, filename: string) {
-	data, ok := os.read_entire_file(filename)
-	if !ok {
-		fmt.printf("Failed to read file: %s\n", filename)
-		return
-	}
+load_file :: proc(app: ^App, filename: string = "") {
+	buffer: FileBuffer
+	if len(filename) == 0 {
+		buffer = FileBuffer{
+			filename = "",
+			content = "",
+			modified = false,
+			cursor_pos = 0,
+			scroll_y = 0,
+			selection = Selection{start = 0, end = 0, active = false},
+		}
+	} else {
+		data, ok := os.read_entire_file(filename)
+		if !ok {
+			fmt.printf("Failed to read file: %s\n", filename)
+			return
+		}
 
-	buffer := FileBuffer{
-		filename = strings.clone(filename),
-		content = string(data),
-		modified = false,
-		cursor_pos = 0,
-		scroll_y = 0,
-		selection = Selection{start = 0, end = 0, active = false},
+		buffer = FileBuffer{
+			filename = strings.clone(filename),
+			content = string(data),
+			modified = false,
+			cursor_pos = 0,
+			scroll_y = 0,
+			selection = Selection{start = 0, end = 0, active = false},
+		}
 	}
 
 	append(&app.files, buffer)
@@ -836,9 +847,13 @@ move_cursor_to_end_of_line :: proc(file: ^FileBuffer) {
 }
 
 save_file :: proc(file: ^FileBuffer) {
+	if file.filename == "" {
+		fmt.println("No filename, currently this feature is not supported, sorry :-(")
+		return
+	}
 	success := os.write_entire_file(file.filename, transmute([]u8)file.content)
 	if success {
-		file.modified = false
+		// file.modified = false
 		fmt.printf("Saved: %s\n", file.filename)
 	} else {
 		fmt.printf("Failed to save: %s\n", file.filename)