update nighly version and remove stabilized features

src/bin/main.rs

@@ -1,4 +1,3 @@
-#![feature(fs_try_exists)]
 extern crate rust_pathtracer as root;
 
 use root::parsing::config::*;
@@ -161,7 +160,7 @@ fn main() {
     let time = Instant::now();
 
     println!("constructing renderer");
-    if !matches!(fs::try_exists("output"), Ok(true)) {
+    if !matches!(fs::exists("output"), Ok(true)) {
         fs::create_dir("output")
             .expect("failed to create output directory. please create it manually");
     }

src/lib.rs

@@ -1,4 +1,4 @@
-#![feature(fs_try_exists, portable_simd)]
+#![feature(portable_simd)]
 
 #[macro_use]
 extern crate smallvec;

src/parsing/mod.rs

@@ -221,7 +221,7 @@ pub fn construct_world<P: AsRef<Path>>(
         );
         let mut local_material_map = HashMap::new();
         assert!(
-            matches!(std::fs::try_exists(mesh_data.filename.as_str()), Ok(true)),
+            matches!(std::fs::exists(mesh_data.filename.as_str()), Ok(true)),
             "could not find obj file or mtl file {}",
             mesh_data.filename.as_str()
         );