Fix Display of Content and Brief in Console

[zicklag]

Fixes #39.

This is a quick fix for #39 that also makes a couple non-fix changes to the display of content:

• There is now a margin between the title, the brief and the content
• The brief will completely disappear if empty instead of saying "No brief"
• If there is a breif it will be printed between square brackets to distinguish it from the content.

[mhgolkar]

Hi @zicklag and @GoDandrea. Thank you both, for the bug-hunt, fix and approval.

The way append_bbcode was used, created issues in other modules too, so I decided to fix them together as one bug. The other, more important reason why this PR didn't end up in the code, was redesigning Content node for the new v2.x generation. Content node's brief parameter is now an integer, defining how many characters from the beginning of the text should be displayed (instead of being an independent string). -1 value can be used to display full content. During redesign I also took ideas from your PR and issue #39, such as hiding unset brief, making sections distinguishable, and option to display full content.

Thanks again