allocate jmpbuf array in heap
realloc jmpbuf if necessary
[bugfix] unwrap raised error object
initial raise-continuable support
[bugfix] pic_get_args supports 'e' specifier
add guard macro
update doc
unlock some of exception tests
tear off on longjmp
fix memory leak
hold destination stack locations by offset
fix a bug in pic_pop_try
Allocate pic_blocks in picrin's gc pool; reference count may cause problems
unlock dynamic-wind test
mark error handlers
raise-continuable broken
Merge branch 'fix-dynamic-wind'