Debugging support #1: yyprintf DO action name, findRule by index

add action name to yythunk for run-time debugging
definition=    s:identifier needs findRule(yytext, s))
Makefile: fix test target
Debugging support #2: one-line @ "context"

yyprintcontext prints the context for G->text, yytext or G->buf+G->pos only until the next newline
add yyqq to print quotable strings
pass yyDo action names
fix yymatchChar '\\'
print yymatchClass [] strings
check for needed realloc of G->vals on yyPush