c_types: fix c_group (struct group) memory layout
c_types: use libc::{uid_t,gid_t} where appropriate
id: use libc::{uid_t,gid_t} where appropriate
whoami: use libc::uid_t where appropriate
c_types: handle errors from getgroups()/getgrouplist()
Merge pull request #253 from ebfe/fix-c-group

c_types: fix c_group (struct group) memory layout
Merge pull request #254 from ebfe/groups

c_types: handle errors from getgroups()/getgrouplist()
Common function to get user group info
chroot implementation
Remove chroot from todo list
Remove unused debug crate import
Code style fixes
Use gid_t instead of uid_t for groups