* Fixes touchscreen being able to hit 2 targets at a time

* Replaced char "←" with "↩"
* Fixed height
* Removed useless class "noKeyboard"

* Reworked how tracking works for touches

* Added "Source Code" to menu overlay
* Added """credits""" to menu overlay

* Removed Target#init(), as it was unused
* Fixed target respawn sequence from jitters

* Targets now avoid the "←" button when it is available

* Anything "animatiion"-related on target.js has been replaced with
tick()
* Target updates are no longer handled by themselves, but by the game
instance

* Added (currently unused) green target
* Downgraded quality for target sprites

* Split the game's code into 3 scripts: game, menu & target
* Reworked menu
* Time Trials mode has been removed
* The timer setting has been added to all modes
* The timer can now be disabled or set to a custom one (measured in
seconds)
* Added "Time's up!" game over title if the game's timespan has gone
past its duration
* Added a custom input for the target count setting
* Minor changes to the menus and buttons
* Over section now displays the duration of the previous game
* Improved a lot of the target code

* Added 32x32 & 96x96 variants
* Fixed path