syntax-rules

Well, this is imcomplete implementation, but I made this pull-request to make progress and discuss :D
The implementation is separated into piclib/syntax-rules.scm.
As far as I know, those which needs to be fixed are:
* number->string
* check-vars, which checks if pattern-variables of pattern and template are consistent
* matching and expanding vector
* bad logic for matching ellipsis

Thank you.