Time display class, built in types use = not {}

it's cleaner to use = for built in types I think so I changed them back
from int myInt {100} to int myInt = 100;  However classes and structs
still use {}.

Refactored the time display code to use more sfml facilities and
inherited from sf::Text, this way the object contains all the
functionality needed for it's task, the code is simpler.