fist stab at format
added docs for newbie hackers
format supports ~%
minimal tests for format
unbalanced parens
~% test added
princ-to-string to implement ~a and ~S format directives
call write-to-string recursively
reindent
Merge branch 'origin-master' into origin-format

Conflicts:
	jscl.lisp
	src/print.lisp
	src/toplevel.lisp
fixed format for compatibility with new char implementation
Use pop and concatf in basic format
Move hacking tips from the README to HACKING