TODO

Android version:
* Implement ON / flag 44.

iPhone version:
* Preferences looks a bit ugly in iOS 7, because the now-much-smaller switches
  no longer line up with the right margin. How do I create a settings screen
  that looks more like the iOS Settings app?
* Add option to disable key click.
* Haptic feedback option.
* Support landscape mode.
* Implement ON / flag 44.

Windows version:
* Press a key with the mouse, then move the mouse outside of the window, then
  release the mouse button. The key stays pressed; apparently the mouse-up is
  not handled in this case.
* What would it take to fix the Alt-Tab problem? How do you create a "new"
  style menu bar? This may be relevant: https://msdn.microsoft.com/en-us/library/windows/desktop/hh270423(v=vs.85).aspx

Mac version:
* When you resize the print-out window, the bottom of the print-out shows stuff
  from the top of the print-out, and it keeps doing that until you restart the
  app. Seems like bounding rectangles getting out of sync.
* Modify the file selection dialogs so they have a file type menu, and add
  extensions to file names automagically when appropriate.
* Implement low-battery checker.

Linux version:
* Update low-battery checker to work with /proc/acpi/battery and
  /sys/class/power_supply.

All versions:
* PRGM paste: accept text from the clipboard and parse it like txt2raw; accept
  URLs and load them as raw files if they look like raw files, and parse them
  like txt2raw otherwise.
* Add a feature for importing and exporting variables from and to CSV files.
* Add link to 42s.pdf in the About box.