implements srfi-17(generalized-set!)
Updates CMakeLists.txt
implement by using (picrin attribute)
fixes small mistakes
setter -> @@setter
Merge pull request #163 from stibear/srfi17

implements srfi-17(generalized-set!)
repl moves to contrib
split repl and main loop
use readline in repl
import (picrin readline) only when exists
add commentary for future work
Merge branch 'repl-and-readline'
[repl] support multiple line input
hyper link srfi's pages
add missing link of srfi 17
add missing link of srfi 111
grammar bugfix
[doc] getopt dependency was dropped.
vm_tear_off should happen in cont. saving, not in restoring
lset/lref can access to torn-off regions because of call/cc