Wrote an enum class to represent commands for serial communication.
Created an abstract class for serial packets and an implementation of
this class for each different command specified in the enum. Reading or
writing serial information will utilize these classes.
Made changes to serial protocol.
Wrote Controller class to handle all tasks in a queue and automatically
execute tasks at the specified time.

Wrote Task class to encapsulate all info for a given task (time,
duration, and angles).
Made SerialComm abstract and added an abstract method called
handleRxData. This method is called by the serial port's event listener
when is receives data. 

Controller now creates an inner class called ArduinoComm extending
SerialComm that implements this method to handle incoming packets.