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/bar_modules/bar_module_cpu.rs

@@ -116,6 +116,11 @@ impl UnibarModuleCpu {
 
 impl bar_modules::BarModuleActions for UnibarModuleCpu {
 
+    // --------------------
+    fn get_name(&self) -> String {
+        return "UnibarModuleCpu".to_string();
+    }
+
     // --------------------
     fn clear(&mut self) {
         self.cpu_times_sample_1 = CpuTimes::new();