Change ModifiersState to a bitflags struct (#1306)

* Change ModifiersState to a bitflags struct

* Make examples work

* Add modifier state methods

* all things considered, only erroring out in one file throughout all of these changes is kinda impressive

* Make expansion plans more clear

* Move changelog entry

* Try to fix macos build

* Revert modifiers println in cursor_grab

* Make serde serialization less bug-prone

Cargo.toml

@@ -25,6 +25,7 @@ libc = "0.2.64"
 log = "0.4"
 serde = { version = "1", optional = true, features = ["serde_derive"] }
 raw-window-handle = "0.3"
+bitflags = "1"
 
 [dev-dependencies]
 image = "0.21"
@@ -48,9 +49,6 @@ version = "0.1.3"
 default_features = false
 features = ["display_link"]
 
-[target.'cfg(any(target_os = "ios", target_os = "windows"))'.dependencies]
-bitflags = "1"
-
 [target.'cfg(target_os = "windows")'.dependencies.winapi]
 version = "0.3.6"
 features = [