Update documentation-theme-light to new theme system

[jainanshul]

I am trying to use https://github.com/documentationjs/documentation-theme-light with the latest code for documentationjs like below.

./node_modules/.bin/documentation \
  build \
  src/*.js\
  -f html \
  -t node_modules/documentation-theme-default \
  --name test

and I keep getting error

docs/node_modules/documentation/lib/commands/build.js:60
      throw err;
      ^

TypeError: theme is not a function
    at Object.makeHTML [as html] (docs/node_modules/documentation/lib/output/html.js:21:3)
    at onDocumented (docs/node_modules/documentation/lib/commands/build.js:63:47)
    at docs/node_modules/documentation/index.js:101:7
    at docs/node_modules/documentation/lib/input/dependency.js:45:5
    at ConcatStream.<anonymous> (docs/node_modules/documentation/node_modules/concat-stream/index.js:36:43)
    at emitNone (events.js:72:20)
    at ConcatStream.emit (events.js:166:7)
    at finishMaybe (docs/node_modules/documentation/node_modules/concat-stream/node_modules/readable-stream/lib/_stream_writable.js:475:14)
    at endWritable (docs/node_modules/documentation/node_modules/concat-stream/node_modules/readable-stream/lib/_stream_writable.js:485:3)
    at ConcatStream.Writable.end (docs/node_modules/documentation/node_modules/concat-stream/node_modules/readable-stream/lib/_stream_writable.js:455:41)

[tmcw]

documentation-theme-light is not yet updated for the new theme system.

[jainanshul]

Is there a timeline on when that would be supported?

[tmcw]

I'm working on it right now, but I'd happily accept a PR to speed this up. This is a relatively big project, with lots of work to do, and we could really use more contributors!

[tmcw]

Working on our theme interface... kind of tricky here. Options are:

• Themes look like function (comments, options, utils, callback) where utils is an object with createLinkerStack and createFormatters
• or Themes rely on documentation as a dependency
• or Themes rely on a documentation-utils module as a dependency