HyperCard transitions extremely slow

[chrisparana]

Certain transitions in HyperCard are extremely slow, making most stacks unusable.

[clemens-unterkofler]

It's because Hypercard installs a timer for 3ms while the timer interrupt is only processed every 16ms. (and it also installs a timer that never fires, adding further delay)

[chrisparana]

@kanjitalk755 corrected this issue in their version by back porting the high precision timer from SheepSaver. There's no iOS build in that repo though so it would be nice to have this applied here.