Support a better rendering of cards on errbot -T

[gbin]

BotPlugin.send_card is a mapping to Slack Attachments and Hipchat Cards. It is also implemented on the graphics backend (-G) to display nicely the various elemets. Now for all the other backends included Text, it rolls back to a card.md template to generate the card the best it can.

This generation is pretty ugly on the Text backend, we might want to present it in a more simple way with no table etc like: Card Title content Link to image: link key: value key:value

[sijis]

Could this issue be elaborated? Are there issues in Test or is it adding additional supported formats?

[gbin]

@sijis done. Thx !