Add a function to the DSL that outputs all the known DSL attributes + their values

[orta]

Before I've done something like this in the Dangerfile:

message "Insertions: #{insertions}"
message "Added: #{files_added}"
message "LOC: #{lines_of_code}"
message "Mod: #{files_modified}"

Which isn't great. Instead I should be able to add something like message_all_attributes or something. It would show all of the information in a nice table.

[orta]

Aha!

These details can be added to the Danger message, we can hide them inside a HTML attribute that is not stripped ( similar to what we do to detect if it's come from Danger ) aweeeesome

[orta]

#40 and #44 cover this - the commit sha is in the message and --verbose gives you all the info