Added mechanism to skip updates in a module

* This is useful in modules where HTTP API calls are made. Updating them
  every second is expensive, network intensive and can cause rate limits
  to be hit
* Added get_name() function to modules for easier debug statements

src/common/mod.rs

@@ -18,6 +18,12 @@ impl fmt::Display for TemperatureUnits {
     }
 }
 
+#[derive(Debug,PartialEq,Eq,Copy,Clone)]
+pub enum UpdateResult {
+    Update,
+    Skip
+}
+
 // --------------------
 // Application options
 // --------------------
@@ -29,4 +35,5 @@ pub struct AppOptions {
     pub music_progress:     bool,
     pub debug:              bool,
     pub debug_modules:      bool,
+    pub debug_update:       bool,
 }