MSCP_SSH_AUTH_PASSWORD passes a password, and MSCP_SSH_AUTH_PASSPHRASE passes a passphrase for publickey auth. They enable avoiding interactive password input. Test cases are also added.
and remove --dirty from git-describe-based versioning
doc/mscp.rst is generate from mscp.1 by make generate-mscp-rst. README is also updateded to reference doc/mscp.rst.