add devpts mount and fix umount error(mistaked commands) bugs.
add pre/post commit hook
Merge branch 'feature/add-pre_post-hook' into develop
change default arch, i386 to amd64.
add devpts handler
Merge branch 'develop' of https://github.com/fumihito/core-prep into develop

Conflicts:
	customize/_40customize-chroot.sh
Merge branch 'release/RELv0.2'