Added error handling to msfvenom when generating payloads

Added error handling to msfvenom when generating payloads
Fixed msfvenom when displaying options
Altered msfvenom options to match msfpayload...

Altered msfvenom options to match msfpayload summary
Cleaned up msfvenom a bit
msfvomon - arguments are not case sensitive

Kind of a dirty hack....
Land #2027 - Fix multiple issues with msfvenom

[FixRM:#8096]
[FixRM:#8095]
[FixRM:#8094]