In GimpSpinButton, don't propagate Enter key-press events if
updating the spin-button's value in response changes the entered
text. This prevents confirming dialogs when hitting Enter after
entering a math expression in size entries, updating their value
instead.
Likewise, don't propagate Escape key-press events if a new value
was entered, and restore the original value instead.
In GimpSpinButton, adjust the scroll step in response to modifiers:
normal scrolling uses the step increment, Ctrl uses the page
increment, and Shift scales the step increment down by the ratio
between the page and step increments (up to the minimal precision
of the spin button).
This applies to all spin buttons used in GIMP, including spin
scales.
When the "wrap" property of a GimpSpinButton is TRUE, wrap-around
out-of-range values entered through the spin-button's text entry,
instead of clamping them. Since we're using GimpSpinButton
everywhere since last commit, this applies to all our angle-entry
spin buttons (including spin scales).
GimpSpinButton is a drop-in replacement for (and a subclass of)
GtkSpinButton. Unlike GtkSpinButton, it avoids updating the
adjustment value when losing focus, unless the entry text has
changed. This prevents accidental loss of precision, when the
adjustment value can't be accurately displayed in the entry.