Fixed: CPNumber>>numberWithBool: breaks CPComparisonPredicate

Commit df2be92 breaks CPComparisonPredicate if one side of the comparison is a property which returns a BOOL.

CPPredicateParser parses literal BOOLs (YES/NO) into 0/1 using CPNumber>>numberWithBool:. CPComparisonPredicate however does not cast a BOOL from a property using numberWithBool:. E.g.

[[YES,NO] filteredArrayUsingPredicate:[CPPredicate predicateWithFormat:'self = YES']]
used to return [true], now it returns [].

This fix addresses the issue by "typecasting" the lhs/rhs values to numbers using CPNumber>>numberWithBool: if they are of type boolean.

Fixes #2028
NEW: CPCoding for CPAttributedString
Fixed: support for dates (CPDatePicker) in CPPredicateEditor

Before this commit, row templates and views belo,ging to them were copied via archiving/unarchiving.
This was causing problems when the view was not completely CPCoding compliant, like for CPDatePicker.

With this commit, template views use CPCopying (-copy method) when available.
Also added CPCopying for CPDatePicker as a category in CPPredicateEditor.

Test: in CPPredicateEditorTest, on the right panel, choose a keypath, operator, and select 'Dates' in the popup for the right expression.

Fixes #2041
Merge branch 'refactor-locale' into fix-CPNumber-numberWithBool
Fixed: Broken Documentation.
Docs: Added @class to make_headers documentation,
Fixed: Textual CPDatePicker issue with number of digit

Previously, the day/month/hour of the textual datePicker had always two digits, even when the number was under 10. For instance the day 8 was displayed 08.
Now it's like in cocoa, 8 is displayed 8.

Fixes #2059
Merge pull request #2044 from krodelin/fix-CPNumber-numberWithBool

Fixed: CPNumber>>numberWithBool: breaks CPComparisonPredicate
Merge pull request #2054 from cacaodev/CPPredicateEditor-dates

Fixed: support for dates (CPDatePicker) in CPPredicateEditor
fixing editing semantics
minor fix
editing fix
fixed one last minor glitch
yet another minor fix
unit-tests + simplification
more protection against edge cases
formatting
formatting
more formatting
Formatting: CPAttributedStringTest.

Refs #2045.