core: config: add config option to enable the wayland input method

Having multiple input methods at once causes behaviour defined by the
Wayland compositor. In a recent update by Phoc, the most recently
started input method would take priority to demonstrate the instability.
Add a configuration option so the Wayland input method can be disabled
to accommodate a second input method.

Also update the README with the new option.

README.md

@@ -110,3 +110,4 @@ Configuration example:
     
     wayland:
       height: 185
+      input-method: true

src/core/config.rs

@@ -16,6 +16,7 @@ pub struct Configuration {
     repeat: u64,
     layout: String,
     wayland_height: i32,
+    wayland_im_enable: bool,
 }
 
 impl Configuration {
@@ -30,6 +31,13 @@ impl Configuration {
             let height = height.expect("Wayland height should be a 32-bit signed integer");
             self.wayland_height = height;
         }
+
+        let im_enable = yaml.get(&Yaml::String(String::from("input-method")));
+        if let Some(im_enable) = im_enable {
+            let im_enable = im_enable.as_bool();
+            let im_enable = im_enable.expect("Wayland height should be a 32-bit signed integer");
+            self.wayland_im_enable = im_enable;
+        }
     }
 
     pub fn load() -> Result<Self, LoadError>
@@ -39,6 +47,7 @@ impl Configuration {
             repeat: 25,
             layout: String::from("latn_qwerty_us.xml"),
             wayland_height: 185,
+            wayland_im_enable: true,
         };
 
         if let Ok(file) = File::open("/etc/unfettered-keyboard.yaml") {
@@ -106,4 +115,10 @@ impl Configuration {
     {
         self.wayland_height
     }
+
+    #[inline(always)]
+    pub fn wayland_im_enable(&self) -> bool
+    {
+        self.wayland_im_enable
+    }
 }