SLexer: added NA types and ellipses to builtin symbols
SLexer: added NA types and ellipses to builtin symbols

tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments,tomstuart/pygments