RMC_AddCaption function.
Add a caption to a region of an existing chart
Syntax
	nResult& = RMC_AddCaption( ByVal nCtrlId&, ByVal nRegion&, ByValsCaption$, Optional ByVal nBackColor&, Optional ByVal nTextColor&, Optional ByVal nFontsize&, Optional ByVal nFontbold& )
Parameter
	nCtrlId&
		Unique ID of the chart control, to which the caption belongs.
	nRegion&
		Region to which the caption belongs.
	sCaption$
		The caption with a maximum length of 200 chars.
	nBackColor&
		BackColor of the caption as a Color... constant. If omitted or 0, no backcolor will be drawn.
	nTextColor&
		Textcolor of the caption as a Color... constant. If omitted or 0: ColorBlack.
	nFontsize&
		Fontsize in points, which is used to draw the caption. If omitted or 0: 9 points.
	nFontbold&
		If TRUE, font is bold. If omitted or 0: FALSE.
Return value
	0
		No error, function succeeded.
	RMC_ERROR_CTRLID
		Wrong control ID (0 or no chart with this control ID was found).
	RMC_ERROR_MAXREGION
		The region index exceeds the maximum possible numbers of regions (6) within a chart control.
	RMC_ERROR_WRONGREGION
		The region index is inexistent in the chart control.