Reshaper for Burp v1.6.0

Added new When constraints: When Content Type, When Mime Type.
Added new Then action: Then Set Encoding.
Added Setting to allow the default encoding used for reading and writing HTTP messages to be changed.
Added undo (CTRL-Z) to all text fields.
Added "default" as an file reading/saving encoding option.
Fixed negation of When Event Direction actions.
Fixed the inability to disable capture of Proxy messages.