Move fade() to F.fadeViewToAlpha()
Call setTextColor() in F.setKeyColor() wrapper
Set background shape color filter in setKeyColor()

Though it turns out it's a GradientDrawable, not a ShapeDrawable.
Use white shapes and filter the color dynamically
Don't switch between identical background shapes
Rename keypad_key_normal to keypad_key
Remove unused keypad_key_pressed drawable
Fade only the dark keypad, not the live one

This cuts the number of animations in half.  The only difference is that
the keypad will be slightly brighter in mid-fade.  This can be explained
as follows:  Imagine that both colors were white.  With this change, you
would always see white, whereas before, in mid-fade you'd get half white
and half half-white, i.e. 75% light gray.  Arguably, the new behavior is
correct.
Rename dark keypad to fake keypad

We're going to have the inactive keypad pressed into service (ha ha) for
purposes besides being a dark replica of the real keypad, such as fading
highlights.
Add ids to fake keys

We need a reference to each key individually so we can use them one at a
time for fading highlights.  The exception is Enter, since animating its
highlight fade would interfere with fading to the dark keypad.
Add Data.fakeKeyIds[]

Store the ids of the fake numeric keys in an array, indexed by the key's
name.  This is an easy way to get from the live key to the fake one.
Add setCounterpart() and getCounterpart()

Add a setCounterpart() method to explicitly specify the fake counterpart
to a live key.  Add getCounterpart() to determine it from a numeric name
otherwise and memoize the result.  (The Enter key's counterpart fake key
isn't used individually and doesn't get specified.)
Store eraseKey, enterKey as Key, not View
Explicitly set the counterpart of the erase key
Merge branches 'color-filter' and 'counterpart-keys' into fade-out
Set fake key color dynamically
Fade key from cyan to red on touch-up
Remove unused drawable/keypad_key_disabled.xml
Remove unused Key.Disabled attributes
Merge branch 'fade-out'