Create RainfallData.java

/** 
 *  Program that reads in the average monthly rainfall for a city for each 
 *  month of the year and then reads in the actual monthly rainfall for each 
 *  of the previous 12 months. Program then outputs a formatted table to show
 *  deviations from the average. Program uses an object called RainfallData to
 *  store the average rainfall, the actual rainfall and the deviation (whether
 *  it be positive or negative). The program contains a method display() which
 *  outputs a table of the data.
 */