some patches for keyboard managment

[Pierre-Yves Rivaille]

Here are a few straight forward patches for :
- NSBrowser, to fix a <tab> problem (focus was not moving properly when
    tab was pressed due to a missing return)
- NSCell, pressing <space> when a cell is selected does not only send
    an action but does also change the state of the selected cell
    (NSOnOffButton for example -> try the preview button of the
    NSFontPanel)
- NSPanel, setting the nextKeyView chain so one can navigate using
    tab/shift-tab in the AlertPanels

The last patch is about NSFontPanel :
- it sets up a nextKeyView chain (again)
- it changes defer:NO to defer:YES for performance
    (i don't see any reason to use defer:NO)
- if overrides NSWindow fieldEditor:forObject: in order not to give to
    sizeField the common fieldEditor, otherwise selecting the sizeField
    NSTextField sets the current font of the NSFontPanel to the font used
    by sizeField (Helvetica 12 normal on my system), reseting all the
    changes made to the current font. So it gives sizeField a fieldEditor
    with usesFontPanel set to NO.

Pierre-Yves

NSCell.m.patch
Description: Text document

NSBrowser.m.patch
Description: Text document

NSPanel.m.patch
Description: Text document

NSFontPanel.m.patch
Description: Text document