Add idStr::(V)Format(), make idList compatible with C++ foreach

idStr::(V)Format() is a static (v)printf-like function that returns
and idStr. Can be used like a better va(), or for
idStr mystr = idStr::Format( "number of items: %d", myarr.Num() );

neo/idlib/Str.cpp

@@ -1785,6 +1785,48 @@ idStr idStr::FormatNumber( int number ) {
 	return string;
 }
 
+idStr idStr::Format( const char* format, ... )
+{
+	va_list argptr;
+	va_start( argptr, format );
+	idStr ret = VFormat( format, argptr );
+	va_end( argptr );
+	return ret;
+}
+
+idStr idStr::VFormat( const char* format, va_list argptr )
+{
+	idStr ret;
+	int len;
+	va_list argptrcopy;
+	char buffer[16000];
+
+	// make a copy of argptr in case we need to call D3_vsnprintf() again after truncation
+#ifdef va_copy // IIRC older VS versions didn't have this?
+	va_copy( argptrcopy, argptr );
+#else
+	argptrcopy = argptr;
+#endif
+
+	len = D3_vsnprintfC99( buffer, sizeof(buffer), format, argptr );
+
+	ret.EnsureAlloced( len + 1 );
+	if ( len < sizeof(buffer) ) {
+		strcpy( ret.data, buffer );
+		ret.len = len;
+	} else {
+		// string was truncated, because buffer wasn't big enough.
+		// ret.EnsureAlloced( len + 1 ) already made sure that ret
+		// has a big enough buffer, so print into that directly
+		D3_vsnprintfC99( ret.data, len+1, format, argptrcopy );
+		ret.len = len;
+	}
+	va_end( argptrcopy );
+
+	return ret;
+
+}
+
 // behaves like C99's vsnprintf() by returning the amount of bytes that
 // *would* have been written into a big enough buffer, even if that's > size
 // unlike idStr::vsnPrintf() which returns -1 in that case

neo/idlib/Str.h

@@ -325,6 +325,9 @@ public:
 	int					DynamicMemoryUsed() const;
 	static idStr		FormatNumber( int number );
 
+	static idStr		Format( const char* format, ... )  id_attribute((format(printf,1,2)));
+	static idStr		VFormat( const char* format, va_list argptr );
+
 protected:
 	int					len;
 	char *				data;

neo/idlib/containers/List.h

@@ -132,6 +132,25 @@ public:
 	void			Swap( idList<type> &other );						// swap the contents of the lists
 	void			DeleteContents( bool clear );						// delete the contents of the list
 
+#if __cplusplus >= 201103L
+	// begin and end allow using C++11 for(ElemType& e : myIdlist) { ... }
+	type* begin() {
+		return list;
+	}
+
+	const type* begin() const {
+		return list;
+	}
+
+	type* end() {
+		return list + num;
+	}
+
+	const type* end() const {
+		return list + num;
+	}
+#endif
+
 private:
 	int				num;
 	int				size;