Mail: Tweak the height of the menu fields

Since hrev45725 we no longer resize fixed sized menu fields to their preferred
height in the constructor so as to be backwards compatible with the behavior on
BeOS R5. As a consequence though, the menu fields in Mail are now a bit too
tall so this commit tweaks the menu fields to be just a bit shorter matching
the height of the text controls.
BColorControl: Style fixes

* Update copyright in header, add my name, alphabetize.
* Rename _ColorRamp() to _DrawColorRamp().
* Rename update parameter to updateRect
BColorControl: Create _SetCellSize() method

...eliminating duplicated code.
BColorControl: Size text rect based on font size

* Also change kMinCellSize from a uint32 to a float so that it can be used
  with std::min() and std::max() instead of min_c() and max_c().
* Set the text controls sizes and margins based on the font size. Also rework
  _TextRectOffset() so that it will get the right spacing from by dividing the
  palette frame by 3.
* Replace bare numbers and refactor with calculation or magic constant.
* Create a private method _TextRectOffset() which calculates and
  returns the vertical text rect offset to use based on the font size.
* Replace 2.0 with new kBevelSpacing constant where appropriate.
* fPaletteFrame calculation in _LayoutView() was refactored but should
  not have changed.
BColorControl: Rename bevelRect to just rect

... with an explanatory comment. Correct similar comment.
Tiny style fix.
BColorControl: Introduce a _PaletteFrame() method

... eliminating duplicate code.
BColorControl: Introduce kRampCount magic constant.
BColorControl: Refactor _LayoutView()

In a few cases we were doing the work of _LayoutView() twice because
we called _LayoutView() and then called ResizeToPreferred() which called
_LayoutView() again.

Now only call ResizeToPreferred() which calls _LayoutView().
BColorControl: Position text controls better

Position the text control vertically in the middle of the ramp in
the case that the text controls are pushed down so that the red, green,
and blue text controls are next to the red, green, and blue ramps.