Added pom.xml of maven.
Added namespace "tennistdd.java.reloadcountdown" to class TestCountdown and Countdown. Moved class TestCountdown to directory "src/test/java" and Countdown to "src/main/java".
Set the package name "tennistdd.java.reloadcountdown" for class TestCountdown and Countdown.
Moved method waitForSeconds() from class TestCountdown to Countdown.
Decreased seconds after sleeping.
Moved class TestCountdown and Countdown to a new package "tennistdd.reloadcountdown".
Initialized the field "seconds" of the class Countdown to be 0.
Renamed the test name to be "countdown_starting_count_from_one_should_be_stopped_after_one_second".
Renamed class Countdown to be Gun.
Renamed class TestCountdown to be GunTest.
Renamed tests and variables to reflect the concepts of gun, firing interval, etc.
Added test "pull_trigger_of_a_gun_in_the_middle_of_a_firing_interval_will_make_a_clicking_sound".
Merge pull request #5 from wubin28/master

Renamed from "Countdown" to "Gun".