remember timestamp of the input event
extract quit logic to ShouldQuit
simplify code a bit
flattern code a bit
move time logic on top of the main loop
code style fix
rename {since_last_time => elapsed_time}
allow user to get status of *all* keys at once
move code all around
moving system out of the logic loop
use aliasing to simplify the code
move draw to where it belongs

draw => render
start extracting update method, lambda are awesome
extracting ...
extracting ...
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Merge branch 'extract_update_method'