Stage encoding is now SaveRegister aware
Fix two cosmetic typos
Update 3 more encoders to be StageEncoder compatible

This could probably use some DRY love via a mixin
Unblock when invalid encoder is selected and allow multiple encoder
Rescue only NoEncodersSucceededError to pass the tests
Choose fallback if stage encoding fail
Switch to Array#union and rename preserved_registers
Fix suggested stuff
https://github.com/hmoore-r7/metasploit-framework/pull/2
Merge pull request #2 from agix/multipleStageEncoders

Unblock when invalid encoder is selected and allow multiple encoder
Fix up the StageEncodingFallback logic and error handling
Address the two open comments from @jlee-r7
Land #3770, resolve random stager bugs