Added amazonS3 mediaHandler and updated handler interface

Signed-off-by: Tom Wright <tom@inflatablecookie.com>
Fixed typo in hash generator task

Signed-off-by: Tom Wright <tom@inflatablecookie.com>
Added transferFile method to mediaHandlers

Signed-off-by: Tom Wright <tom@inflatablecookie.com>
Added devtools transfer task handler

Signed-off-by: Tom Wright <tom@inflatablecookie.com>