Check server-supported authentication methods against what authentication methods the user provided
Check server-supported authentication methods against what authentication methods the user provided

Also move emitting of a simple error into its own function since it's used in several places, and probably more in the future

Drooids/ssh2,ianscrivener/ssh2,mcanthony/ssh2,Student007/ssh2,laktek/ssh2-chromeify,ianscrivener/ssh2,onilabs/ssh2,mscdex/ssh2,mcanthony/ssh2,ArielAbreu/ssh2,mscdex/ssh2,mscdex/ssh2,jskirst/sftp-to-http,mscdex/ssh2,mafintosh/ssh2,mafintosh/ssh2,24hr/ssh2,24hr/ssh2,laktek/ssh2-chromeify,Student007/ssh2,ArielAbreu/ssh2,mafintosh/ssh2,laktek/ssh2-chromeify,Drooids/ssh2,jskirst/sftp-to-http,onilabs/ssh2