Implement glob ignores (#272)

* Add Glob wrapper type with better serialization

* Introduce PathIgnoreRule struct

* Implement equality for Glob type

* Add PathIgnoreRule to InstanceContext

* Implement glob ignores in directory middleware

* Fix up filters

* Use Iterator::all instead of loop

* Add project-level configuration for glob ignores

* Add test project for glob ignores

* Wire up project file and snapshots to make glob ignores work

* Better codepaths for adding ignore rules with empty iterators

* Add test for globs inherited from parent projects

* Add test details, support glob ignores in nested projects

* Add feature flag for globs

* Switch to use ExactSizeIterator instead of size_hint

* Remove glob visitor

rojo-test/src/build_test.rs

@@ -45,6 +45,13 @@ gen_build_tests! {
     txt_in_folder,
 }
 
+#[cfg(feature = "unstable_glob_ignore_paths")]
+gen_build_tests! {
+    ignore_glob_inner,
+    ignore_glob_nested,
+    ignore_glob_spec,
+}
+
 #[test]
 fn build_plain_txt() {
     run_build_test("plain.txt");