Initializing site in a new directory does not generate boilerplate directory

[nicholaschuayunzhi]

1. $ markbind init ./dir_does_not_exist_yet
2. _boilerplates directory not created

Offending lines:
https://github.com/MarkBind/markbind-cli/blob/e1e47cf66d36359233368ced9745bbc709704678/lib/Site.js#L83-L101

Due to ENOENT error in:
http://man7.org/linux/man-pages/man2/mkdir.2.html

EDIT: To clarify problem is as such:

Above commands want to create ./dir_does_not_exist_yet/_boilerplates
but /dir_does_not_exist_yet does not exist yet. So ENOENT will be thrown

If reproducible, possible first timer issue?

[nicholaschuayunzhi]

Fixed in #167