Fix collision with modified cgSymbol.pro

Because I wanted extra symbols with the ease of calling cgSymbol(), I modified
said routine to do so.  But, since cgSymbol() assumes the use of cgPS_Open,
which did not come about until after I had written mydevice.pro and myps.pro
that I use exclusively for the plots.  I had added a line into my modified
version of cgSymbol.pro to define the COMMON block _$FSC_PS_START_ and CG
structure ps_struct to appease a line in cgSymbol.pro.

Well, if one defines their IDL search path placing the distance-omnibus code
at the end, the IDL-COYOTE version of cgSymbol() is used, causing pukage.

So, I placed the line defining  _$FSC_PS_START_ and ps_struct into myps.pro
and renamed my extras version of the routine as cgSymbol_extra.pro, and shifted
any repository routines that need those extra symbols to point to my routine,
and otherwise the stock cgSymbol() will be called.

	renamed:    utils/cgsymbol.pro -> utils/cgsymbol_extra.pro
	modified:   utils/myps.pro