Enable wrapping of variables in the variables view

I also added an option for this, which made it easier for me to debug.
I haven't added it to the prefs yet.

TODO:

- Add the option to the prefs.

- Allow to turn on wrapping on a per-variable basis ('w' will turn this
  on and off in the variables,   view, and there will also be an option
  in the variable inspection options window).

- Right now, wrapped lines beyond the first line are indented two
  spaces.  This is the same as what digging into a variable looks like,
  which make it confusing (granted, digging in still indents further,
  but it's harder to follow).  I think variables that are sub variables
  should have some kind of character preceding them, like:

    varname: [1, 2, 3]
    + 0: 1
    + 1: 2
    + 2: 3

- When variables are not wrapped, there should be an ellipses at the
  end.  When unicode is supported, we can use …, otherwise, we use ...