support for ecdsa ssh key.

- add ssh key support (ecdsa)
- update validator.py
- modify help.py balloon and add warning

Regards!
@abadger Actually, this regex is here to only check 'rsa' & 'ssh-rsa' by removing leading and trailing spaces. It can be removed as we (or an admin) explicitly define the list or the string we (admin) want to check against.
If he add .strip() to ssh_keysupport, this regex is not required.