added readInputFromFile
-added readInputFromFile that takes input and populates it with data from the file
-changed > to < in checkForMissedDeadline
-changed the name of generateInput to userInput and moved all user input to this method (no Scanner in main)
-added some javadoc, changed new ArrayList to diamond notation etc

Input file must be in the top project directory (name "input.txt") with the following structure:
N
PHASE_1 PERIOD_1 EXECUTION_1
PHASE_2 PERIOD_2 EXECUTION_2
...
PHASE_N PERIOD_N EXECUTION_N
END_OF_TIME

input.txt is a good example of input file.