added mssql_escalate_executeas module
fixed code comment
comment fix-sorry
Add getsid to the python meterpreter
Don't fail if username_from_token returns None
update from master
Do minor cleanup
Use snake_case in filename
Land #4120, @nullbind's module for MS SQL privilege escalation

* through ESCALATE AS
Land #4157 - Add getsid to python meterpreter
Merge branch 'upstream/master' of github.com:rapid7/metasploit-framework