Replaced some of the hardcoded values with constants (misc)

- Replaced several hardcoded values with the appropriate enums.
- Added documentation for some hardcoded values that haven't been
  replaced by enums (yet)
- Minor code legibility improvements.

Signed-off-by: Haru <haru@dotalux.com>
Replaced some of the hardcoded values with constants (login)

- Replaced several hardcoded values with the appropriate enums.
- Added documentation for some hardcoded values that haven't been
  replaced by enums (yet)
- Minor code legibility improvements.

Signed-off-by: Haru <haru@dotalux.com>
Replaced some of the hardcoded values with constants (char)

- Replaced several hardcoded values with the appropriate enums.
- Added documentation for some hardcoded values that haven't been
  replaced by enums (yet)
- Minor code legibility improvements.

Signed-off-by: Haru <haru@dotalux.com>
Replaced some of the hardcoded values with constants (map)

- Replaced several hardcoded values with the appropriate enums.
- Added documentation for some hardcoded values that haven't been
  replaced by enums (yet)
- Minor code legibility improvements.

Signed-off-by: Haru <haru@dotalux.com>
Added messages to discourage running Hercules as root.

- You should not run Hercules as root, period.
- If you understand all of the security implications, and still want to
  do so (and you don't want to be bothered by the warning messages),
  open core.c and uncomment the line:
  "//#define I_AM_AWARE_OF_THE_RISK_AND_STILL_WANT_TO_RUN_HERCULES_AS_ROOT"
- If you're running Hercules as root because your provider forces (or
  encourages) you to do so, it means they're really doing it wrong, so
  please complain to them and ask them for an alternative.
- More info on the topic:
  http://www.tldp.org/HOWTO/Security-HOWTO/local-security.html
  http://www.gentoo.org/doc/en/security/security-handbook.xml?style=printable&part=1&chap=1#doc_chap4
  http://wiki.centos.org/TipsAndTricks/BecomingRoot
  http://fedoraproject.org/wiki/Configuring_Sudo
  https://help.ubuntu.com/community/RootSudo
  http://www.freebsdwiki.net/index.php/Root

Signed-off-by: Haru <haru@dotalux.com>