start to support live mode (#73)

1. add a liveMode flag to config, when liveMode is set, the timer
will keep running even though all the actions casted
2. add a public method addEvent, which will cast newly added event
in sync
3. move mouse in sync mode with the latest position info

src/types.ts

@@ -241,6 +241,7 @@ export type playerConfig = {
   showWarning: boolean;
   showDebug: boolean;
   blockClass: string;
+  liveMode: boolean;
 };
 
 export type playerMetaData = {