core: end simple pv name (e.g., $xy) at end of line

- cfg parser was throwing error if last token in a line was $xy as pv
  with \n was not found

cfg.lex

@@ -1100,7 +1100,7 @@ IMPORTFILE      "import_file"
 <PVARID>{ID}|'\.'			{yymore(); }
 <PVARID>{LPAREN}			{	state = PVAR_P_S; BEGIN(PVAR_P);
 								p_nest=1; yymore(); }
-<PVARID>.					{	yyless(yyleng-1);
+<PVARID>{CR}|{EAT_ABLE}|.	{	yyless(yyleng-1);
 								count();
 								addstr(&s_buf, yytext, yyleng);
 								yylval.strval=s_buf.s;