Update locale docs to match new reality.

Created docs for NumberFormat, DateFormat, DateTimeFormat, and TimeFormat
and moved the docs from BLocale to the respective new file. Also
DurationFormat was updated as well.

doxygen once again compiles the docs without warnings.

headers/os/locale/NumberFormat.h

@@ -19,9 +19,9 @@ enum BNumberElement {
 
 class BNumberFormat : public BFormat {
 public:
-		BNumberFormat();
-		BNumberFormat(const BNumberFormat &other);
-		~BNumberFormat();
+								BNumberFormat();
+								BNumberFormat(const BNumberFormat &other);
+								~BNumberFormat();
 
 								// formatting