add helper method to AppContext to simplify getting options

src/formats/mtk_pkg/mod.rs

@@ -44,7 +44,6 @@ pub fn is_mtk_pkg_file(app_ctx: &AppContext) -> Result<Option<Box<dyn Any>>, Box
 pub fn extract_mtk_pkg(app_ctx: &AppContext, ctx: Box<dyn Any>) -> Result<(), Box<dyn std::error::Error>> {
     let mut file = app_ctx.file().ok_or("Extractor expected file")?;
     let ctx = ctx.downcast::<MtkPkgContext>().expect("Missing context");
-    let no_del_comp = app_ctx.options.iter().any(|e| e == "mtk_pkg:no_del_comp");
 
     let file_size = file.metadata()?.len();
     let header = ctx.decrypted_header;
@@ -153,7 +152,7 @@ pub fn extract_mtk_pkg(app_ctx: &AppContext, ctx: Box<dyn Any>) -> Result<(), Bo
             match decompress_lzhs_fs_file2file(&out_file, lzhs_out_path) {
                 Ok(()) => {
                     println!("- Decompressed Successfully!");     
-                    if !no_del_comp {
+                    if !app_ctx.has_option("mtk_pkg:no_del_comp") {
                         //after successfull decompression remove the temporary .lzhs file
                         fs::remove_file(&output_path)?;
                     }