PySSHGui: basic qt-designer interface skeleton
PySSHGui/ssh_config.py: use os.path.expanduser to easily locate ~/.ssh/config
PySSHGui: provide SSH_Config object to PySSHGui
PySSHGui/ssh_config: don't add any final empty host
PySSHGui: create list of radio buttons, one per each host, based on content provided by SSH_Config class (which reads ~/.ssh/config)
pySSHGui.ui: change grid layout to vertical
PySSHGui: implemented removal of hosts at GUI level