uses view based approach and shows bools, arrays and objects as it should, the remaining as text.

TODO: In-cell editing
Text alignment in cells
Edits and saves date using the date picker.
Strings can be edited (but not very polished)
Now floats and doubles can also be edited, although the locale is ignored, so “12,3” will not be accepted. Should use the formatter, which should be kept a reference to.
Strings can also be edited.

TODO: Commit change with enter, instead of cmd-enter
Transition to view based basically complete
All types (except array and object) are editable in-cell.
Date is additionally editable using the old popup date picker, by double clicking

TODO:
Edit arrays, objects
Switch to showing all decimals of floats and doubles when entering edit mode - now these are truncated when edited.
Fixed some details
Fixed a problem with the boolean:

    NSNumber *result = @(sender.state == NSOnState);

actually doesn’t work! Doing

    CFNumberGetType((CFNumberRef)result)

reveals that the term in brackets is interpreted as an kCFNumberSInt32Type, rather than a kCFNumberCharType. With a cast to BOOL it works though.

    NSNumber *result = @((BOOL)(sender.state == NSOnState));
Fixed the truncation issue when editing cells…

…by storing the actual number in the textfield and displaying THAT when a cell gets focus (firstResponder)
numberformatter should be decimalstyle even for ints
Fixed table column widths.
Fixed tooltips for column headers.
Simplifications in the code.
Adding and removing rows
Changed preambles.
Merge pull request #756 from GreatApe/gk-browser-view-based

The main window is now view based