added multiple payload and stage encoding in msfconsole

set EncodersList x86/shikata_ga_nai,x86/alpha_upper
will encode the payload directly in msfconsole with shikata_ga_nai then alpha_upper.

metsvc.dll can be detected by IDS.
With StageEncodersList variable, you can add a list of custom encoder to your stage.
(Just tested with meterpreter)
Warning, encode the dll with shikata_ga_nai can take a very long time (almost 4 min)
set StageEncodersList x86/custom_encoder,x86/custom_encoder2