revise readme
update readme
scan.l cleanup
emit additional scanner header file
use noyywrap option
use yyget_extra function
add pic_intern
use volatile string
use yyrealloc
remove useless includes
add an alias 'yylval' linked to '*yylvalp'
use yyfree/yyalloc during bytevector lex
use pic_deflibrary in init.c
change default library in repl
my own read impl.
cleanup
update readme
Merge branch 'read'. close #21
remove pic_list, and add pic_listn
typedef pic_value pic_list